To solve for z in the equation 4z + 8 = 20, we need to isolate z on one side of the equation. Here’s how we can do that:

1. Start with the equation: 4z + 8 = 20

2. Subtract 8 from both sides of the equation to isolate the term with z:
   4z + 8 – 8 = 20 – 8
   4z = 12

3. Divide both sides of the equation by 4 to solve for z:
   (4z)/4 = 12/4
   z = 3

Therefore, the solution to the equation 4z + 8 = 20 is z = 3.