12-42=x

Solution for 12-42=x equation:

Simplifying
12 + -42 = x

Combine like terms: 12 + -42 = -30
-30 = x

Solving
-30 = 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.
-30 + -1x = x + -1x

Combine like terms: x + -1x = 0
-30 + -1x = 0

Add '30' to each side of the equation.
-30 + 30 + -1x = 0 + 30

Combine like terms: -30 + 30 = 0
0 + -1x = 0 + 30
-1x = 0 + 30

Combine like terms: 0 + 30 = 30
-1x = 30

Divide each side by '-1'.
x = -30

Simplifying
x = -30