\(\frac{z + 6}{3}\) = \(\frac{2z}{4}\) Multiply both sides by 3
z + 6 = \(\frac{(3)2z}{4}\) 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