x+12+x-9=x

Solution for x+12+x-9=x equation:

Simplifying
x + 12 + x + -9 = x

Reorder the terms:
12 + -9 + x + x = x

Combine like terms: 12 + -9 = 3
3 + x + x = x

Combine like terms: x + x = 2x
3 + 2x = x

Solving
3 + 2x = x

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '-1x' to each side of the equation.
3 + 2x + -1x = x + -1x

Combine like terms: 2x + -1x = 1x
3 + 1x = x + -1x

Combine like terms: x + -1x = 0
3 + 1x = 0

Add '-3' to each side of the equation.
3 + -3 + 1x = 0 + -3

Combine like terms: 3 + -3 = 0
0 + 1x = 0 + -3
1x = 0 + -3

Combine like terms: 0 + -3 = -3
1x = -3

Divide each side by '1'.
x = -3

Simplifying
x = -3