Find the Inverse of the Function $$f ( x ) = \frac { x } { 3 } - 6$$

Multiple Choice

Find the inverse of the function.
- $$f ( x ) = \frac { x } { 3 } - 6$$

A) $f ^ { - 1 } ( x ) = x + 9$
B) $f ^ { - 1 } ( x ) = 3 x + 6$
C) $f ^ { - 1 } ( x ) = 3 x - 18$
D) $\mathrm { f } ^ { - 1 } ( \mathrm { x } ) = 3 \mathrm { x } + 18$