20=x(x+1)

Solution for 20=x(x+1) equation:

Simplifying
20 = x(x + 1)

Reorder the terms:
20 = x(1 + x)
20 = (1 * x + x * x)
20 = (1x + x2)

Solving
20 = 1x + x2

Solving for variable 'x'.

Reorder the terms:
20 + -1x + -1x2 = 1x + -1x + x2 + -1x2

Combine like terms: 1x + -1x = 0
20 + -1x + -1x2 = 0 + x2 + -1x2
20 + -1x + -1x2 = x2 + -1x2

Combine like terms: x2 + -1x2 = 0
20 + -1x + -1x2 = 0

Factor a trinomial.
(4 + -1x)(5 + x) = 0

Subproblem 1
Set the factor '(4 + -1x)' equal to zero and attempt to solve:

Simplifying
4 + -1x = 0

Solving
4 + -1x = 0

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

Add '-4' to each side of the equation.
4 + -4 + -1x = 0 + -4

Combine like terms: 4 + -4 = 0
0 + -1x = 0 + -4
-1x = 0 + -4

Combine like terms: 0 + -4 = -4
-1x = -4

Divide each side by '-1'.
x = 4

Simplifying
x = 4
Subproblem 2
Set the factor '(5 + x)' equal to zero and attempt to solve:

Simplifying
5 + x = 0

Solving
5 + x = 0

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

Add '-5' to each side of the equation.
5 + -5 + x = 0 + -5

Combine like terms: 5 + -5 = 0
0 + x = 0 + -5
x = 0 + -5

Combine like terms: 0 + -5 = -5
x = -5

Simplifying
x = -5
Solution
x = {4, -5}