Steps:
4x + 8 = 2x + 7 + 2x - 20
Group like terms:
4x + 8 = 2x + 2x + 7 - 20
Add similar elements: 2x + 2x = 4x
4x + 8 =4x + 7 - 20
Add/Subtract the numbers: 7 - 20 = -13
4x + 8 = 4x - 13
Subtract 8 from both sides
4x + 8 - 8 = 4x - 13 - 8
Simplify:
4x = 4x - 21
Subtract 4x from both sides:
4x - 4x = 4x - 21 - 4x
Simplify
0 = -21
Hope this helps! :) and Happy Halloween! ~Zane