=4x(x-20)

Solution for =4x(x-20) equation:

Simplifying
0 = 4x(x + -20)

Reorder the terms:
0 = 4x(-20 + x)
0 = (-20 * 4x + x * 4x)
0 = (-80x + 4x2)

Solving
0 = -80x + 4x2

Solving for variable 'x'.
Remove the zero:
80x + -4x2 = -80x + 4x2 + 80x + -4x2

Reorder the terms:
80x + -4x2 = -80x + 80x + 4x2 + -4x2

Combine like terms: -80x + 80x = 0
80x + -4x2 = 0 + 4x2 + -4x2
80x + -4x2 = 4x2 + -4x2

Combine like terms: 4x2 + -4x2 = 0
80x + -4x2 = 0

Factor out the Greatest Common Factor (GCF), '4x'.
4x(20 + -1x) = 0

Ignore the factor 4.
Subproblem 1
Set the factor 'x' equal to zero and attempt to solve:

Simplifying
x = 0

Solving
x = 0

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

Simplifying
x = 0
Subproblem 2
Set the factor '(20 + -1x)' equal to zero and attempt to solve:

Simplifying
20 + -1x = 0

Solving
20 + -1x = 0

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

Add '-20' to each side of the equation.
20 + -20 + -1x = 0 + -20

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

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

Divide each side by '-1'.
x = 20

Simplifying
x = 20
Solution
x = {0, 20}