## Algebra 1: Common Core (15th Edition)

Both of the sides are equal: $X + 12 = X + 12$ Subtract 12 from both sides $X = X$ Subtract X from both sides $0 = 0$ The number 0 is equal to 0 Therefore both sides are equal
$X + 12 = X + 12,$ Subtract 12 from both sides, $X = X,$ Subtract X from both sides, $0 = 0,$ The number 0 is equal to 0, \$ Therefore both sides are equal