Answer:
Direct.
Step-by-step explanation:
A varies directly as the square of r.
Answer:
width = 2 units
Step-by-step explanation:
If the length of a rectangle is (x) units, then that means that the width of a rectangle is x - 4 units.
the area of a rectangle is length * width
so just substitute the values that we have now.
x (length) * (x-4) width = 12 (area of rectangle)
so that gives us
x^2 - 4x =12
subtract 12 from both sides
x^2 - 4x - 12 =0
now factor this equation
x^2 + 2x - 6x -12 = 0
x(x+2) - 6(x+2) = 0
(x-6)(x+2) = 0
x = 6, or x = -2 REMEMBER THAT VALUE OF x = LENGTH, IT CANNOT BE NEGATIVE AS YOU CANT HAVE NEGATIVE VALUE OF A SIDE
length = 6, and width = 6 -4 = 2
Answer:
Alexander is incorrect because the expressions are not equivalent.
Step-by-step explanation:
If the expression is evaluated for any value of x, y; the result will not be same.
For instance, let assume x = 1 and y = 2
3x + 4y = 3 + 4 = 7
(3)(4) + xy = (3)(4) + (1 * 2) = 12 + 2 = 14
So, the expressions are not the same and Alexander is incorrect.
Answer:
The 90% confidence interval for the mean test score is between 77.29 and 85.71.
Step-by-step explanation:
We have the standard deviation for the sample, so we use the t-distribution to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 25 - 1 = 24
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 24 degrees of freedom(y-axis) and a confidence level of
. So we have T = 2.064
The margin of error is:

In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 81.5 - 4.21 = 77.29
The upper end of the interval is the sample mean added to M. So it is 81.5 + 4.21 = 85.71.
The 90% confidence interval for the mean test score is between 77.29 and 85.71.