The composition of a function and its inverse is always

The composition of a function and its inverse is always give the identity of the function f (x) = x. For example, you are given the function f (x) = 3x - 2 and you are to find its inverse function f ₋₁ (x).

f (x) = 3x - 2

y = 3x - 2

y + 2 = 3x

x = (y + 2) / 3

y = (x + 2) / 3

f ⁻1 (x) = (x + 2) / 3