Question

What is the inverse of the function f(x) = x – 12?

Answer 1

F^-1(x)=12+x hope this is what you need

Answer 2

To find the inverse, simply swap x and f(x) and solve for f(x).
x = f(x) - 12
-f(x) = -x -12
f(x)^-1 = x + 12