
=

Multiply both sides by 3
z + 6 =

Multiply both sides by 4
(4)z + 6 = (3)2z Simplify
4z + 24 = 6z Subtract 4z from both sides
24 = 2z Divide both sides by 2
12 = z Flip the sides to make it easier to read
z = 12
Turn f(x) into y so the equation is y=x+2. Now switch their places so it is x=y+2. Now solve for y. The answer is y=x-2.
The left side of the equal sign is exactly the same as the right side, so it has infinitely many solutions.