He bought three $10 shirts and six $7 shirts.
Answer:
7
Step-by-step explanation:
The average rate of change of f(x) in the close interval [ a, b ] is

Here [ a, b ] = [2, 5 ]
f(b) = f(5) = 2(5)² - 7(5) = 50 - 35 = 15
f(a) = f(2) = 2(2)² - 7(2) = 8 - 14 = - 6, thus
average rate of change =
=
= 7
If the student received marks of 84, 78, 84, and 72 on her four normal tests, her weighted mean grade is 81.2 percent.
<h3>What is mean?</h3>
The mean is described as a single number that indicates either the closed value for each item in the collection of data or the mean value for the whole set of data.
On her four regular tests, a student had grades of 84, 78, 84, and 72 out of 100. She received 86 percent on her class projects and 78 percent on the final test.
You may compute the weighted mean as follows:

Hence, if the student had marks of 84, 78, 84, and 72 on her four normal tests, her weighted mean grade would be 81.2 percent.
To learn more about the mean refer;
brainly.com/question/22871228
#SPJ1
Answer:
a = - 100
Step-by-step explanation:
Given
= - 10
Multiply both sides by 10 to clear the fraction
a = 10 × - 10 = - 100
Hello.
Firstly, let's isolate x on the equation:

Now, we can replace 'x' for 'y' and vice-versa:

Hope I helped.