Mathematics for IGCSE & O level - Functions (Section 1 - No. 38)

If f(x) = x + 2, then f^-1(x) is:

x - 2

2 - x

1/(x+2)

-x - 2

To find the inverse, swap x and y (where y = f(x)) and solve for y. So, y = x+2 becomes x = y+2, thus y = x-2.