Simplifying
12x + -18 = 90
Reorder the terms:
-18 + 12x = 90
Solving
-18 + 12x = 90
Solving for variable 'x'.
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Move all terms containing x to the left, all other terms to the right.
Add '18' to each side of the equation.
-18 + 18 + 12x = 90 + 18
Combine like terms:
-18 + 18 = 0
0 + 12x = 90 + 18
12x = 90 + 18
Combine like terms:
90 + 18 = 108
12x = 108
Divide each side by '12'.
x = 9
Hence,
x = 9
Hope this helps! <3