300=x(x+20)

Solution for 300=x(x+20) equation:

Simplifying
300 = x(x + 20)

Reorder the terms:
300 = x(20 + x)
300 = (20 * x + x * x)
300 = (20x + x2)

Solving
300 = 20x + x2

Solving for variable 'x'.

Reorder the terms:
300 + -20x + -1x2 = 20x + -20x + x2 + -1x2

Combine like terms: 20x + -20x = 0
300 + -20x + -1x2 = 0 + x2 + -1x2
300 + -20x + -1x2 = x2 + -1x2

Combine like terms: x2 + -1x2 = 0
300 + -20x + -1x2 = 0

Factor a trinomial.
(10 + -1x)(30 + x) = 0

Subproblem 1
Set the factor '(10 + -1x)' equal to zero and attempt to solve:

Simplifying
10 + -1x = 0

Solving
10 + -1x = 0

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

Add '-10' to each side of the equation.
10 + -10 + -1x = 0 + -10

Combine like terms: 10 + -10 = 0
0 + -1x = 0 + -10
-1x = 0 + -10

Combine like terms: 0 + -10 = -10
-1x = -10

Divide each side by '-1'.
x = 10

Simplifying
x = 10
Subproblem 2
Set the factor '(30 + x)' equal to zero and attempt to solve:

Simplifying
30 + x = 0

Solving
30 + x = 0

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

Add '-30' to each side of the equation.
30 + -30 + x = 0 + -30

Combine like terms: 30 + -30 = 0
0 + x = 0 + -30
x = 0 + -30

Combine like terms: 0 + -30 = -30
x = -30

Simplifying
x = -30
Solution
x = {10, -30}