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

Multiple Choice

For the given function f(x) , find f-1(x) .
-f(x) = x + 6

A) $f ^ { - 1 } ( x ) = \frac { x } { 6 }$
B) $f ^ { - 1 } ( x ) = x - 6$
C) $f ^ { - 1 } ( x ) = 6 - x$
D) $f ^ { - 1 } ( x ) = - x + 6$