What is the answer to 2/6 + 1/2?

This is the simplified difference quotient for the function f(x) = 6 - 4x - x^2. The difference quotient is a formula used to find the average rate of change of a function over a given interval.

In this case, we are given the function f(x) = 6 - 4x - x^2 and asked to simplify the difference quotient (f(x) - f(a))/(x - a). To simplify this expression, we need to first substitute the given function into the formula and evaluate. So we have:
(f(x) - f(a))/(x - a) = (6 - 4x - x^2 - [6 - 4a - a^2])/(x - a)
Next, we can simplify the numerator by combining like terms and distributing the negative sign:
= (-4x - x^2 + 4a + a^2)/(x - a)
We can further simplify by factoring out a negative sign and rearranging the terms:
= -(x^2 + 4x - a^2 - 4a)/(x - a)

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An 80% confidence interval for the population mean H is (42.56, 47.68).

Part 1:

The formula for a confidence interval for the population mean is:

CI = x ± z*(σ/√n)

where x is the sample mean, σ is the population standard deviation, n is the sample size, and z is the critical value from the standard normal distribution corresponding to the desired confidence level.

For an 80% confidence interval, the z-value is 1.28 (obtained from a standard normal distribution table). Plugging in the values, we get:

CI = 45.12 ± 1.28*(8.9/√50) = (42.56, 47.68)

Therefore, an 80% confidence interval for the population mean H is (42.56, 47.68).

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If there is a positive correlation between x and y in the regression equation y = bx + a, then b > 0.

In the regression equation, y = bx + a, a positive correlation between x and y indicates that as the value of x increases, the value of y also increases, and vice versa. The correlation between these two variables is represented by the coefficient b in the equation.

A positive correlation means that b > 0, as a positive value for b will result in y increasing when x increases. On the other hand, if b < 0, it would indicate a negative correlation, meaning that y would decrease as x increases.

The constant term a in the equation represents the y-intercept or the value of y when x is equal to zero. It does not directly affect the correlation between x and y, so it can be either positive (a > 0) or negative (a < 0) depending on the specific data being analyzed. The value of a will only shift the position of the regression line on the graph, while the slope (b) determines the direction of the correlation between the variables.

In conclusion, if there is a positive correlation between x and y in the regression equation y = bx + a, then b > 0. The values of a > 0 or a < 0 are not directly related to the correlation between x and y.

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In which the altitude from D to side AB bisects AB, the angles of the rhombus are: 120, 60, 120, and 60.

An angle is formed when two straight lines or rays meet at a common endpoint. The common point of contact is called the vertex of an angle. The word angle comes from a Latin word named ‘angulus,’ meaning “corner.”

To solve this question, we need to know the basic theory related to the quadrilateral. As we know rhombus is a type of quadrilateral and also It is a special case of a parallelogram, whose diagonals intersect each other at 90 degrees. Here, by using various theorems or properties we will Find the angles of the rhombus.

Given that ABCD is a Rhombus and DE is the altitude on AB then AE = EB

In a △AED and △BED,

DE = DE (common line)

∠AED = ∠BED (right angle)

AE = EB (DE is an altitude)

∴ △AED ≅ △BED (SAS property)

∴ AD = BD (by C.P.C.T)

But AD = AB ( Sides of rhombus are equal)

[tex]\rightarrow \sf AD = AB = BD[/tex]

∴ ABD is an equilateral triangle.

[tex]\sf \therefore\angle A = 60^0[/tex]

[tex]\sf \rightarrow\angle A =\angle C = 60^\circ[/tex] (opposite angles of a rhombus are equal)

Always, when we add adjacent angles of a rhombus, it is supplementary in nature.

[tex]\sf \angle ABC + \angle BCD = 180^0[/tex]

[tex]\sf \rightarrow \angle ABC + 60^0=180^0[/tex]

[tex]\sf \rightarrow \angle ABC = 180^0-60^0=120^0[/tex]

[tex]\sf \therefore \angle ABC = \angle ADC = 1200[/tex]. (opposite angles of rhombus are equal)

∴ Angles of rhombus are ∠A = 60° and ∠C = 60°, ∠B = ∠D = 120°.

Therefore, option (B) is the correct answer.

Note: Rhombus has all its sides equal and so does a square. Also, the diagonals of any square are perpendicular (means 90°) to each other and bisect the opposite angles. Therefore, a square is a type of rhombus. In rhombus the opposite angles are equal to each other. Also, in rhombus the diagonals bisect these angles.

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ABCD is a rhombus in which Altitude from D to side AB bisects AB. Find the angles of the rhombus? Altitude from D to side AB bisects AB.

A. 110, 70, 110, 70

B. 120, 60, 120, 60

C. 125, 55, 125, 55

D. 135, 45, 135, 45

Based on the Alternate Interior Angles Theorem, the measure of angle 3 in the image attached below is: 100°

If we have a situation where two parallel lines are intersected by a transversal, according to the Alternate Interior Angles Theorem, the pairs of alternate interior angles formed are congruent.

Angles 7 and 3 lie in the interior sides of the parallel lines but on opposite sides of the transversal, which makes them alternate interior angles. Therefore, based on the Alternate Interior Angles Theorem, we have:

m<3 = m<7

Substitute:

m<3 = 100°

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Are you good with basic maths

The orthonormal basis for W is {u_1, u_2, {1, 0, -2}}.

To find an orthonormal basis for W, we first need to normalize the given vectors v_1 and v_2 by dividing each by their magnitude.

The magnitude of v_1 is sqrt(3^2 + (-5)^2 + 6^2) = sqrt(70), so the normalized vector u_1 is (3/sqrt(70), -5/sqrt(70), 6/sqrt(70)).

Similarly, the magnitude of v_2 is sqrt((3/2)² + (9/2)² + 3^2) = 3sqrt(2), so the normalized vector u_2 is (3/2sqrt(2), 9/2sqrt(2), 3/sqrt(2)).

Now, to check if u_1 and u_2 are orthogonal, we take their dot product, which is (3/sqrt(70))*(3/2sqrt(2)) + (-5/sqrt(70))*(9/2sqrt(2)) + (6/sqrt(70))*(3/sqrt(2)) = 0. Therefore, u_1 and u_2 are indeed orthogonal.

Finally, we can verify that the vector {1, 0, -2} is also orthogonal to both u_1 and u_2.

Thus, the orthonormal basis for W is {u_1, u_2, {1, 0, -2}}.

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The antiderivative of the original expression, with a constant of integration c is (1/7) * e^(7x-1) / (-6(7x)^6) + c

We want to compute the antiderivative of the expression 7ex − 1 / (7x)7 dx. To do so, we can use the formula for integration by substitution, which states that if we have an integrand of the form f(g(x))g'(x), we can substitute u = g(x) and rewrite the integral in terms of u and du/dx. This allows us to simplify the integral and hopefully make it easier to solve.

So let's apply this formula to the given expression. We notice that we have an exponential function, which suggests that we should try to let u be the exponent. Specifically, we can let u = 7x, so that we have:

u = 7x

du/dx = 7

dx = du/7

Now, we can substitute these expressions for u and dx into the integral:

∫ 7ex−1 / (7x)7 dx

= ∫ 7eu−1 / (7u/7)7 * (du/7) (using the substitutions above)

= (1/7) ∫ e^(u-1)/u^7 du

We can simplify the integral a bit further by using the formula for the antiderivative of e^x, which is simply e^x + c. In this case, we have e^(u-1) in the integrand, so we can write:

(1/7) ∫ e^(u-1)/u^7 du

= (1/7) * e^(u-1) / (-6u^6) + c

Now we can substitute back in our original variable, x, to obtain the final antiderivative:

= (1/7) * e^(7x-1) / (-6(7x)^6) + c

And that's it! This is the antiderivative of the original expression, with a constant of integration c.

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The correct conversion of the number 0.0000783 to scientific notation is:7.83 x 10⁻⁶

The general form of scientific notation is: a x 10n, where a is the coefficient and n is the exponent.In this case, Tyler converted 0.0000783 to scientific notation as 78.3 x 10⁻⁶, which is incorrect. Tyler's mistake is that he did not shift the decimal point to the right one place to get the coefficient of 7.83, which is the correct coefficient. Therefore, the main answer is No, the coefficient should be 7. 83.The correct conversion should be:0.0000783 = 7.83 x 10⁻⁶

In conclusion, Tyler made an error when he converted 0.0000783 to scientific notation. Instead of 78.3 x 10⁻⁶, the correct scientific notation for 0.0000783 is 7.83 x 10⁻⁶.

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In the given frequency table, the relative frequency of 24 represents the proportion of family members who chose to go on a hike out of the total number of family members.

To calculate the relative frequency, we divide the frequency of the specific category (in this case, hike) by the total frequency. In this case, the frequency of the hike is 24, and the total frequency is 38.

Relative Frequency = Frequency of Hike / Total Frequency

Relative Frequency = 24 / 38

Simplifying the fraction, we get:

Relative Frequency ≈ 0.632

So, the relative frequency of 24 represents approximately 0.632 or 63.2%. This means that around 63.2% of the family members chose to go on a hike at the family reunion.

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The equation for the ellipse is x²/625 + y²/400 = 1

To write an equation for an ellipse centered at the origin, which has foci at (0,±15) and vertices at (0,±25),

we use the formula:

x²/a²+y²/b²=1

where a represents the distance from the center to the vertex and c is the distance from the center to the focus.

The distance from the center to the foci is 15 and the distance from the center to the vertices is 25.

The center is located at the origin which means (h, k) = (0, 0).

Thus, a=25, c=15

Since c is the distance from the center to the focus, then

b² = a² − c²

where a = 25 and c = 15.

Substituting in the formula:

b2 = 25² − 15²

b2 = 400

Thus, the equation for the ellipse is:

x²/625 + y²/400 = 1

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The power series expansion for () =[tex]∫x^3ln(1+x) dx centered at x=0 is +∑((-1)^n*x^(n+4))/(n(n+4)).[/tex]

The power series expansion of the indefinite integral ∫x^3ln(1+x) dx, centered at x=0, is given by ∑((-1)^n*x^(n+4))/(n(n+4)), where the summation index starts from n=1 to infinity.

The first 5 nonzero terms of the power series are: -(x)^5/5 + x^6/12 - x^7/21 + x^8/32 - x^9/45. The open interval of convergence for this power series is (-1, 1). This means that the power series representation is valid for all x values between -1 and 1, inclusive.

It's important to note that the convergence at the endpoints of the interval should be checked separately. In summary, the power series expansion provides an approximation of the indefinite integral ∫x^3ln(1+x) dx within the interval (-1, 1).

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The statement you made is not entirely correct. The Second Shape Theorem, also known as the Second Derivative Test, does not include the converse of the First Shape Theorem. Instead, it provides additional information about the nature of critical points of a function.

The Second Shape Theorem states that if a function f(x) has a critical point at x = a (i.e., f'(a) = 0), and if f''(a) exists and is nonzero, then the function has a local minimum at x = a if f''(a) > 0, and a local maximum at x = a if f''(a) < 0.

Note that this theorem only applies to critical points where f'(a) = 0. There may be other critical points where f'(a) does not equal zero, and these points do not satisfy the conditions of the Second Shape Theorem.

In contrast, the converse of the First Shape Theorem states that if a function is differentiable at a point x = a and f'(a) = 0, then f has an extreme value at x = a. This is a separate theorem that is not directly related to the Second Shape Theorem.

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The Second Shape Theorem states that if a function f(x) has an extreme value at x=a, then the function must also be differentiable at x=a. This theorem is the converse of the First Shape Theorem, which states that if a function is differentiable at a point, then it must have a local extreme value at that point.

Essentially, the Second Shape Theorem tells us that having an extreme value at a point is a necessary condition for differentiability at that point. This theorem is particularly useful in calculus and optimization problems, where we are interested in finding the maximum or minimum values of a function. By checking for extreme values and differentiability at those points, we can determine if a function has a local maximum or minimum.

Your statement, "If f(x) has an extreme value at x=a, then f is differentiable at x=a," is actually the converse of the First Shape Theorem. However, this statement is not universally true, as extreme values can occur at non-differentiable points (e.g., sharp corners or endpoints). The Second Shape Theorem does not include the converse of the First Shape Theorem, but rather provides another method for identifying extreme values by analyzing the second derivative.

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Therefore, the equation of the set of all points equidistant from a and b is -4x - 5y - 4z + 49 = 0.

The set of all points equidistant from two points is the perpendicular bisector of the line segment joining the two points.

The midpoint of the line segment joining a and b is

M = ((-1+5)/2, (5+1)/2, (4-1)/2) = (2, 3, 3/2)

The direction vector of the line segment joining a and b is

d = b - a = (5+1, 1-5, -1-4) = (6, -4, -5)

Therefore, a vector perpendicular to the line segment is

n = (6, -4, -5) x (1, 0, 0) = (-4, -5, -4)

We can take any point on the perpendicular bisector, say P, and write an equation for the line passing through P and perpendicular to n. Then, we can solve for the point(s) where this line intersects the plane perpendicular to n and passing through M. These points will be equidistant from a and b.

Let P = (x, y, z) be a point on the perpendicular bisector. Then, the vector joining P and M is

v = P - M = (x-2, y-3, z-3/2)

Since v is perpendicular to n, we have

v · n = 0

or

(-4, -5, -4) · (x-2, y-3, z-3/2) = 0

which simplifies to

-4x - 5y - 4z + 49 = 0

This is the equation of the plane perpendicular to n and passing through M. Any point on this plane will be equidistant from a and b.

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The answer is 7.99996224.

To find the area of the region described, we first need to determine the points of intersection between the three equations. The first two equations intersect when 8,192 √x = 128x^2. Simplifying this equation, we get x = 1/64. Plugging this value back into the equation y = 8,192 √x, we get y = 8.
The second and third equations intersect when 128x^2 = y = 8,192 √x. Simplifying this equation, we get x = 1/512. Plugging this value back into the equation y = 128x^2, we get y = 1.
Therefore, the region described is bounded by the lines y = 8, y = 8,192 √x, and y = 128x^2. To find the area of this region, we need to integrate the difference between the two functions that bound the region, which is (8,192 √x) - (128x^2), with respect to x from 1/512 to 1/64.
Evaluating this integral gives us the exact area of the region, which is 7.99996224 square units. Therefore, the answer is 7.99996224.

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Answer:

f(x)=3*3+8*2-7x-4 = 9x + 5

g(2)=2x-6 = 2(x-3)

The given statement "Shanice, who is 55 years old and has been a steelworker for 30 years, is unemployed because the steel plant in his town has closed and moved to a new location." indicates that Shanice is a Structural Unemployed.

In light of the given scenario, Shanice, a 55-year-old worker, is unemployed as the steel plant in her town has closed and moved to a new location. Structural unemployment is characterized by a disparity between the jobs available in the market and job seekers or a decrease in demand for a particular type of worker as a result of technological
changes or an economic shift. In this case, the economic shift is due to the closing of the plant.

Structural unemployment is long-term unemployment that is caused by a mismatch between job seekers' skills or locations and employers who have jobs available. When the steel plant in Shanice's town shut down and moved to a new location, it caused a decrease in demand for steelworkers, which resulted in Shanice's structural unemployment.

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The consequence of violating the assumption of Sphericity can be significant. It reduces statistical power, effects the distribution of the F-statistic, and raises the rate of Type I errors in post hocs.

Sphericity refers to the homogeneity of variances between all possible pairs of groups in a repeated-measures design. When this assumption is violated, it can result in a distorted F-statistic, which in turn affects the results of post hoc tests.
The correct answer to the question is c. It reduces statistical power, effects the distribution of the F-statistic, and raises the rate of Type I errors in post hocs. This means that violating the assumption of Sphericity leads to a decreased ability to detect true effects, an inaccurate representation of the true distribution of the F-statistic, and an increased likelihood of falsely identifying significant results.
According to statistics, the consequence of violating the assumption of Sphericity is not a rare occurrence. Therefore, it is essential to ensure that the assumptions of your statistical analysis are met before interpreting your results to avoid false conclusions.
In conclusion, violating the assumption of Sphericity can have severe consequences that affect the validity of your research results. Therefore, it is crucial to understand this assumption and check for its violation to ensure the accuracy and reliability of your statistical analysis.

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The function is increasing on the open interval (-0.252, 0.112).

To determine whether a function is increasing on an interval, we need to analyze its first derivative.

If the first derivative is positive on the interval, then the function is increasing.

For the given function f(x) = -6x³ - 8.01x² / 512.604x - 6.48, we can find its first derivative as follows:

f'(x) = [-18x² - 16.02x(512.604x - 6.48) - (-6x³ - 8.01x²)(512.604)] / (512.604x - 6.48)²

Simplifying this expression, we get:

f'(x) = (-3072.624x⁴ + 116.07264x³ + 40.12016x²) / (2626563.904x² - 52832.47552x + 42.12096)

To determine the interval on which the function is increasing, we need to find the values of x for which f'(x) > 0.

We can simplify this inequality by multiplying both sides by the denominator:

(-3072.624x⁴ + 116.07264x³ + 40.12016x²) > 0

We can factor out a common factor of x²:

x²(-3072.624x² + 116.07264x + 40.12016) > 0

The expression inside the parentheses is a quadratic equation, which we can solve using the quadratic formula:

x = (-116.07264 ± √((116.07264)² - 4(-3072.624)(40.12016))) / (2(-3072.624))

x ≈ -0.252, 0.112

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The function f(x) is increasing on the open interval (-∞, ∞).

To determine the intervals on which a function is increasing or decreasing, we need to analyze the sign of its derivative. If the derivative is positive, the function is increasing, and if the derivative is negative, the function is decreasing.

Taking the derivative of f(x):

f'(x) = -18x^2 - 16.02x + 512.604

To find the intervals on which f(x) is increasing, we need to determine where the derivative is positive. So, we solve the inequality:

-18x^2 - 16.02x + 512.604 > 0

Simplifying the inequality, we get:

9x^2 + 8.01x - 256.302 < 0

Using methods such as factoring or the quadratic formula, we find that the roots of the quadratic equation are approximately x ≈ -16.327 and x ≈ 9.027.

By analyzing the intervals between these two values, we can see that the function f(x) is increasing on the open interval (-∞, ∞).

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The solutuion to the given differntial equation is: f(t) = -1/4 e^(2t) + t e^(2t) + 3/4 sin(t)

ℒ{f(t)}(s) = 1/(s^2 - 4s + 5)

We can factor the denominator of the fraction to obtain:

s^2 - 4s + 5 = (s - 2)^2 + 1

Using the partial fraction decomposition, we can write:

1/(s^2 - 4s + 5) = A/(s - 2) + B/(s - 2)^2 + C/(s^2 + 1)

Multiplying both sides by the denominator (s^2 - 4s + 5), we get:

1 = A(s - 2)(s^2 + 1) + B(s^2 + 1) + C(s - 2)^2

Setting s = 2, we get:

1 = B

Setting s = 0, we get:

1 = A(2)(1) + B(1) + C(2)^2

1 = 2A + B + 4C

Setting s = 1, we get:

1 = A(-1)(2) + B(1) + C(1 - 2)^2

1 = -2A + B + C

Solving this system of equations, we get:

A = -1/4

B = 1

C = 3/4

Therefore,

1/(s^2 - 4s + 5) = -1/4/(s - 2) + 1/(s - 2)^2 + 3/4/(s^2 + 1)

Taking the inverse Laplace transform of both sides, we get:

f(t) = -1/4 e^(2t) + t e^(2t) + 3/4 sin(t)

Therefore, the solution to the given differential equation is:

f(t) = -1/4 e^(2t) + t e^(2t) + 3/4 sin(t)

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1. The equation for the total cost of meat and cheese at the deli is: Total cost = 7.99m + 5.99c

2. The expression representing the number of wheelbarrow trips is 4x.

3. The initial height of the materials is -42 feet.

1 In this equation, "m" represents the number of pounds of meat, and "c" represents the number of pounds of cheese. The cost per pound of meat is $7.99, and the cost per pound of cheese is $5.99.

The equation for the total cost of meat and cheese at the deli can be written as:

Total cost = 7.99m + 5.99c

2 In order to determine the number of wheelbarrow trips required to spread all the topsoil, we can divide the total weight of topsoil by the weight of topsoil carried per wheelbarrow trip.

Number of wheelbarrow trips = (8 bags * x lb per bag) / 2 lb per trip

Number of wheelbarrow trips = 4x

Therefore, the expression representing the number of wheelbarrow trips is 4x.

The given equation -42 + 3 models the height of the materials, y, in feet, after x seconds of lifting.

The equation suggests that the crane lifts the materials at a constant rate of 3 feet per second.

3 The initial height of the materials can be determined by evaluating the equation when x is 0:

y = -42 + 3(0)

y = -42 + 0

y = -42

Therefore, the initial height of the materials is -42 feet.

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We know that all the values are within the range of 6.64 to 23.36, so there are no outliers based on this criterion.

To identify any outliers in the given data set {14, 22, 9, 15, 20, 17, 12, 11}, we'll first find the mean and standard deviation.

Mean = (14 + 22 + 9 + 15 + 20 + 17 + 12 + 11) / 8 = 120 / 8 = 15

Next, find the standard deviation:
1. Calculate the squared differences from the mean: (1, 49, 36, 0, 25, 4, 9, 16)
2. Find the average of squared differences: (1 + 49 + 36 + 0 + 25 + 4 + 9 + 16) / 8 = 140 / 8 = 17.5
3. Standard deviation = √17.5 ≈ 4.18

Now, use the standard deviation to identify any outliers. Commonly, an outlier is defined as a data point that is more than 2 standard deviations away from the mean.

Lower limit = Mean - 2 * Standard deviation = 15 - 2 * 4.18 ≈ 6.64
Upper limit = Mean + 2 * Standard deviation = 15 + 2 * 4.18 ≈ 23.36

In the given data set, all the values are within the range of 6.64 to 23.36, so there are no outliers based on this criterion.

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The length of the loan is 13.67 months.

The interest charged for borrowing $600 for 6 months at 8% annual simple interest is:

I = Prt = 600 * 0.08 * (6/12) = $24

Therefore, the interest charged is $24.

The amount due after borrowing $400 for 4 months at 7% annual simple interest is:

I = Prt = 400 * 0.07 * (4/12) = $9.33

The total amount due is:

A = P + I = 400 + 9.33 = $409.33

Therefore, the amount due is $409.33.

The loan is for a principal amount of $700, and $774.67 is repaid at the end of the loan. The interest charged can be calculated as:

A = P(1 + rt) => 774.67 = 700(1 + r*t)

Solving for rt, we get:

rt = (774.67/700) - 1 = 0.10796

Now, we can use the formula for simple interest to find the length of the loan:

I = Prt => I = 700 * r * t

Substituting the value of rt, we get:

I = 700 * 0.10796 = $75.57

The interest charged is $75.57. The interest rate per month is r/12 = 0.08, since the annual interest rate is 8%. Therefore, we can solve for t as:

75.57 = 700 * 0.08 * t

t = 13.67 months

Therefore, the length of the loan is 13.67 months.

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Answer:

B

Step-by-step explanation:

7/8 is the same as 7 times one eighth or 7 divided by 8

Answer:

To solve the problem, we can use the formula:

Total swim time = (time swimming downstream) + (time swimming upstream)

Let's call the speed of the river's current "c". When swimming downstream, the participant's effective speed is 2 + c miles per hour. When swimming upstream, the effective speed is 2 - c miles per hour.

Using the formula above and plugging in the given values, we get:

1.25 = (1.2 / (2 + c)) + (1.2 / (2 - c))

Simplifying this equation requires some algebraic manipulation, but we can eventually arrive at:

c^2 - 1.44 = 0

Solving for c gives us:

c = ±1.2

Since the participant is swimming both downstream and upstream, we know that the current must be flowing in one direction only. Therefore, we take only the positive solution:

The river's current is 1.2 miles per hour.

The scientist descends from 83 feet below sea level to 151 feet below sea level, a change in depth of 151 - 83 = 68 feet. This change occurs over a time of 5 seconds.

The rate of change in depth, or the speed at which the submarine is descending, is given by the ratio of the change in depth to the time taken:

Rate of change in depth = (final depth - initial depth) / time taken

Rate of change in depth = (151 ft - 83 ft) / 5 s

Rate of change in depth = 13.6 ft/s (rounded to one decimal place)

Therefore, the rate of change in the submarine's elevation is 13.6 feet per second.

Rational numbers are indeed closed under the operations of addition, subtraction, and multiplication is true.

We have,

A rational number is any number that can be expressed as a ratio of two integers, where the denominator is not equal to zero.

The set of rational numbers is closed under the operations of addition, subtraction, and multiplication.

This means that if we take any two rational numbers and add them, subtract them, or multiply them together, the result will always be another rational number.

To see why this is true,

Consider two rational numbers a/b and c/d, where a, b, c, and d are integers and b and d are not equal to zero.

To show that rational numbers are closed under addition, we can add the two rational numbers as follows:

a/b + c/d = (ad + bc) / bd

Since a, b, c, and d are all integers, ad + bc is also an integer.

Also, since b and d are not equal to zero, bd is also not equal to zero.

And,

(ad + bc) / bd is a ratio of two integers, where the denominator is not equal to zero.

This means that it is a rational number.

To show that rational numbers are closed under subtraction, we can subtract the two rational numbers as follows:

a/b - c/d = (ad - bc) / bd

Again, since a, b, c, and d are all integers, ad - bc is also an integer, and bd is not equal to zero.

Therefore, (ad - bc) / bd is a rational number.

Finally, to show that rational numbers are closed under multiplication, we can multiply the two rational numbers as follows:

(a/b) x (c/d) = (ac) / (bd)

Once again, ac and bd are integers, and since b and d are not equal to zero, bd is also not equal to zero.

Therefore, (ac) / (bd) is a rational number.

Thus,

Rational numbers are indeed closed under the operations of addition, subtraction, and multiplication.

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The solution of the compound inequality is 4 ≤ x ≤ 6.

The solution of the compound inequality is calculated as follows;

The given inequality equation;

2 + x ≤ 3x – 6 ≤ 12

Break down the compound inequality into two equations as;

2 + x ≤ 3x – 6

add 6 to both sides of the equation;

2 + 6 + x ≤ 3x

8 + x ≤ 3x

Subtract x from both sides of the equation;

8 ≤ 2x

4 ≤ x

Another solution of the inequality is determined as;

3x – 6 ≤ 12

3x ≤ 12 + 6

3x ≤ 18

x ≤ 18/3

x ≤ 6

The solution = 4 ≤ x ≤ 6

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The complete question is below:

Which best describes the solution set of the compound inequality below?

2 + x ≤ 3x – 6 ≤ 12

a: 4 ≤ x ≤ 9

b: 4 ≤ x ≤ 6

c: –2 ≤ x ≤ 2

d: –2 ≤ x ≤ 3

Thus, the balance in the account after 3 years would be $867.97.

To find the balance A in the account after 3 years when Robert invests $800 at 1.8% compound interest annually, we can use the formula :A = P(1 + r/n)^(nt) where P is the principal (initial investment), r is the annual interest rate (as a decimal), n is the number of times the interest is compounded per year, and t is the number of years.

The main answer to the question is to use the formula: A = P(1 + r/n)^(nt) to find the balance A in the account after 3 years when Robert invests $800 at 1.8% compound interest annually.

The formula for finding the balance in a compound interest account after a certain number of years is A = P(1 + r/n)^(nt). Here, P = $800, r = 1.8% = 0.018 (as a decimal), n = 1 (since it is compounded annually), and t = 3 (since the account will be held for 3 years). Plugging in the values gives: A = 800(1 + 0.018/1)^(1*3) = $867.97.

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