An inverse function reverses another function. If f(x) is a function, we write its inverse as f^{-1}(x).

There are three steps to finding an inverse function:

Step 1. Change f(x)= into y=.

Step 2. Swap x and y.

Step 3. Make y the subject.

Let's have a look at an example:

Find the inverse of f(x) = 3x + 4

Step 1. y= 3x + 4

Step 2. x = 3y + 4

Step 3. x - 4 = 3y

(x - 4)/3 = y

So f^{-1}(x) = (x - 4)/3.