Use Composition to Verify Whether or Not the Inverse Is $$f ( x ) = 3 x + 6 , f ^ { - 1 } ( x ) = \frac { 1 } { 3 } x - 3$$

True/False

Use composition to verify whether or not the inverse is correct.
- $$f ( x ) = 3 x + 6 , f ^ { - 1 } ( x ) = \frac { 1 } { 3 } x - 3$$