Find the inverse mentally.
-$$f ( x ) = 7 x - 8$$
A) $f ^ { - 1 } ( x ) = \frac { 8 - x } { 7 }$
B) $f ^ { - 1 } ( x ) = 8 - \frac { x } { 7 }$
C) $f ^ { - 1 } ( x ) = \frac { x + 8 } { 7 }$
D) $f ^ { - 1 } ( x ) = \frac { x } { 7 } + 8$

Question

Quizplus · Accepted Answer

To find the inverse, you swap $x$ and $y$, resulting in $x = 7y - 8$. Solving for $y$, you add 8 to both sides and then divide by 7, giving $y = \frac{x + 8}{7}$, which matches choice C.

Find the Inverse Mentally f(x)=7x−8f ( x ) = 7 x - 8f(x)=7x−8

Find the Inverse Mentally $f ( x ) = 7 x - 8$