Answer:
x = 0
Step-by-step explanation:
AB + BC = AC
therefore
2x+8 + 2x+ 12 = 20
combine like terms
4x+ 20 = 20
Subtraction property of equality
4x + 20 - 20 = 20 - 20
4x = 0
Division property of equality
4x/4 = 0/4
x=0
