Answer
$ x/4 -2=y$
Work Step by Step
In order to find the inverse of a function, we first switch f(x) with y to obtain:
y=4x+8
Because it is an inverse function, that means that we switch x and y and then put the equation in terms of y:
$x=4y+8 \\\\ x-8=4y \\\\ x/4 -2=y$