x*(x-21)=-108

Solution for x*(x-21)=-108 equation:

Simplifying
x(x + -21) = -108

Reorder the terms:
x(-21 + x) = -108
(-21 * x + x * x) = -108
(-21x + x2) = -108

Solving
-21x + x2 = -108

Solving for variable 'x'.

Reorder the terms:
108 + -21x + x2 = -108 + 108

Combine like terms: -108 + 108 = 0
108 + -21x + x2 = 0

Factor a trinomial.
(9 + -1x)(12 + -1x) = 0

Subproblem 1
Set the factor '(9 + -1x)' equal to zero and attempt to solve:

Simplifying
9 + -1x = 0

Solving
9 + -1x = 0

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

Add '-9' to each side of the equation.
9 + -9 + -1x = 0 + -9

Combine like terms: 9 + -9 = 0
0 + -1x = 0 + -9
-1x = 0 + -9

Combine like terms: 0 + -9 = -9
-1x = -9

Divide each side by '-1'.
x = 9

Simplifying
x = 9
Subproblem 2
Set the factor '(12 + -1x)' equal to zero and attempt to solve:

Simplifying
12 + -1x = 0

Solving
12 + -1x = 0

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

Add '-12' to each side of the equation.
12 + -12 + -1x = 0 + -12

Combine like terms: 12 + -12 = 0
0 + -1x = 0 + -12
-1x = 0 + -12

Combine like terms: 0 + -12 = -12
-1x = -12

Divide each side by '-1'.
x = 12

Simplifying
x = 12
Solution
x = {9, 12}