Answer:
a) volume = 321.55 in³
Step-by-step explanation:
volume = 4/3πr³ = 4/3(3.14)4.25³) = 321.55 in³
The expression that is not a variation of the Pythagorean identity is the third option.
<h3>
What is the Pythagorean identity?</h3>
The Pythagorean identity can be written as:

For example, if we subtract cos^2(x) on both sides we get the second option:

Which is a variation.
Now, let's divide both sides by cos^2(x).

Notice that the third expression in the options looks like this one, but the one on the right side is positive. The above expression is in did a variation of the Pythagorean identity, then the one written in the options (with the 1 instead of the -1) is incorrect, meaning that it is not a variation of the Pythagorean identity.
Concluding, the correct option is the third one.
If you want to learn more about the Pythagorean identity, you can read:
brainly.com/question/24287773
He still has 75% of his income left because 1500/375=4 so he spent 1/4 of his check and has 3/4 left.

Therefore, find f(2) and g(2) first before subtracting.

Therefore,

Then find g(2)

Then put f(2) to subtract g(2)

Therefore, the answer is (f-g)(2) = -49.