In this exercise we have to use subtraction knowledge to calculate the final value of the equation, like this:
Letter C
<h2>What is subtraction?</h2>
It is a mathematical operation in which it is possible to find a quantity by decreasing one number by another, it is opposed to addition, being represented by the minus sign.
So make the calculus we have:

See more about subtraction at brainly.com/question/4319655
The second answer with the equilateral triangle
Answer:
The margin of error of u is of 3.8.
The 99% confidence interval for the population mean u is between 27.4 minutes and 35 minutes.
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used 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 = 28 - 1 = 27
99% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 27 degrees of freedom(y-axis) and a confidence level of
. So we have T = 2.7707
The margin of error is:

In which s is the standard deviation of the sample and n is the size of the sample.
The margin of error of u is of 3.8.
The lower end of the interval is the sample mean subtracted by M. So it is 31.2 - 3.8 = 27.4 minutes
The upper end of the interval is the sample mean added to M. So it is 31.2 + 3.8 = 35 minutes
The 99% confidence interval for the population mean u is between 27.4 minutes and 35 minutes.
Answer:
The average value of
over the interval
is
.
Step-by-step explanation:
Let suppose that function
is continuous and integrable in the given intervals, by integral definition of average we have that:
(1)
(2)
By Fundamental Theorems of Calculus we expand both expressions:
(1b)
(2b)
We obtain the average value of
over the interval
by algebraic handling:
![F(5) - F(3) +[F(3)-F(-2)] = 40 + (-30)](https://tex.z-dn.net/?f=F%285%29%20-%20F%283%29%20%2B%5BF%283%29-F%28-2%29%5D%20%3D%2040%20%2B%20%28-30%29)



The average value of
over the interval
is
.
Answer:
B
Step-by-step explanation: