Find the Inverse Mentally $$f ( x ) = \sqrt [ 7 ] { 8 x } + 5$$

Multiple Choice

Find the inverse mentally.
- $$f ( x ) = \sqrt [ 7 ] { 8 x } + 5$$

A) $f ^ { - 1 } ( x ) = ( 8 x ) ^ { 7 } - 5$
B) $f ^ { - 1 } ( x ) = \left( \frac { x - 5 } { 8 } \right) ^ { 7 }$
C) $f ^ { - 1 } ( x ) = \frac { ( x - 5 ) ^ { 7 } } { 8 }$
D) $f ^ { - 1 } ( x ) = \left( \frac { x } { 8 } \right) ^ { 7 } - 5$