x+31=2(x+21)
distribute
x+31 = 2x+42
subtract x from each side
31 = x+42
subtract 42 from each side
-11 =x
Answer: x=-11
Step-by-step explanation:
x+31=2(x+21),
x+31=2x+42
x+31-31=2x+42-31
x=2x+11
x-2x=2x+11-2x
-x=11
x=-11
