Chapter 0 - Before Calculus - 0.4 Inverse Functions - Exercises Set 0.4 - Page 45: 9

$y=\frac{x+6}{7}$

The first step to finding an inverse function is to replace x with y and vice versa. When we do that we get $x=7y-6$. Then we must isolate y. To do this we add 6 to both sides and then divide by 7. That yields $y=\frac{x+6}{7}$