For the Given Function F(x), Find F-1(x) $$f ( x ) = \frac { 3 x + 6 } { 6 x + 9 }$$

For the given function f(x) , find f-1(x) .
- $$f ( x ) = \frac { 3 x + 6 } { 6 x + 9 }$$

A) $f ^ { - 1 } ( x ) = \frac { - 9 x + 6 } { 6 x - 3 }$
B) $\mathrm { f } ^ { - 1 } ( \mathrm { x } ) = \frac { 3 \mathrm { x } + 6 } { 6 \mathrm { x } + 9 }$
C) $f ^ { - 1 } ( x ) = \frac { 6 x - 3 } { - 9 x + 6 }$
D) Not one-to-one