x(x-10)=-21

Solution for x(x-10)=-21 equation:

Simplifying
x(x + -10) = -21

Reorder the terms:
x(-10 + x) = -21
(-10 * x + x * x) = -21
(-10x + x2) = -21

Solving
-10x + x2 = -21

Solving for variable 'x'.

Reorder the terms:
21 + -10x + x2 = -21 + 21

Combine like terms: -21 + 21 = 0
21 + -10x + x2 = 0

Factor a trinomial.
(3 + -1x)(7 + -1x) = 0

Subproblem 1
Set the factor '(3 + -1x)' equal to zero and attempt to solve:

Simplifying
3 + -1x = 0

Solving
3 + -1x = 0

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

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
Subproblem 2
Set the factor '(7 + -1x)' equal to zero and attempt to solve:

Simplifying
7 + -1x = 0

Solving
7 + -1x = 0

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

Add '-7' to each side of the equation.
7 + -7 + -1x = 0 + -7

Combine like terms: 7 + -7 = 0
0 + -1x = 0 + -7
-1x = 0 + -7

Combine like terms: 0 + -7 = -7
-1x = -7

Divide each side by '-1'.
x = 7

Simplifying
x = 7
Solution
x = {3, 7}