Hi, there.
_____
Here's how we can find the inverse of a function:
- Swap x's and y's.
- Solve in terms of y.
(1)

(2)
Divide both sides by 8. Be sure to divide each and every term by 8.

Next, subtract both sides by x/8. Subtract bothsides by y also.

To finish this off divide each and every term by -1.

We can also reduce the fraction 2/8.

We can also write
f⁽⁻¹⁾
instead of y.

Hope the answer - and explanation - made sense,
happy studying.