Simplifying
90 = 10(x + 7)
Reorder the terms:
90 = 10(7 + x)
90 = (7 * 10 + x * 10)
90 = (70 + 10x)
Solving
90 = 70 + 10x
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '-10x' to each side of the equation.
90 + -10x = 70 + 10x + -10x
Combine like terms: 10x + -10x = 0
90 + -10x = 70 + 0
90 + -10x = 70
Add '-90' to each side of the equation.
90 + -90 + -10x = 70 + -90
Combine like terms: 90 + -90 = 0
0 + -10x = 70 + -90
-10x = 70 + -90
Combine like terms: 70 + -90 = -20
-10x = -20
Divide each side by '-10'.
x = 2
Simplifying
x = 2