Answer:
x=13
Step-by-step explanation:
if you will substitute the value of f(x) with 5, you will get the following equation:
5=2x-21
2x=26/÷2
x=13
(I didn't know what you ment when you wrote x2, is it x square or 2X)
I really hope it was the second one, cause that's how I solved it.
