the student has left 75 because if you add 5 and 70 it gives you $75 that's how much the student had left.
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
Answer:
Answer
Let height =h
Total surface area=2πr(r+h)
r=7cm
⇒968=2×
7
22
×7(7+h)
⇒
44
968
=7+h
⇒h+7=22
⇒h=22−7
=15cm.
Step-by-step explanation:
Answer:(0,4)
Step-by-step explanation:
X+y=6
x=10
10+y=6
y=-4
10=-4+z
-4+z=10
z=10+4
z=14
So the correct answer is 14