A useful example is converting between Fahrenheit and Celsius:
To convert Fahrenheit to Celsius:f(F) = (F - 32) x 5/9
The Inverse Function (Celsius back to Fahrenheit) is: f-1(C) = (C × 9/5) + 32
For You: see if you can do the steps to create that inverse.
Click here to view a video that explains converting Fahrenheit to Celsius.