Answer:
x is 10 when f(x) = 7
Explanation:
f(x) is another way of saying y=. The question is basically asking, what is the value of x when the 3/2x - 8 = 7
So, to do this, you are going replace y with it's numerical value. The numerical value given to you is 7. Now, you are going to solve for x (by isolating x).

f(10) = 7
Check your work?
Plug in 10 where you see x.
y = 3/2x - 8
y = (3/2)(10)-8
y = 7 ✅