(-20+-1x)(4+-1x)=0

Solution for (-20+-1x)(4+-1x)=0 equation:

Simplifying
(-20 + -1x)(4 + -1x) = 0

Multiply (-20 + -1x) * (4 + -1x)
(-20(4 + -1x) + -1x * (4 + -1x)) = 0
((4 * -20 + -1x * -20) + -1x * (4 + -1x)) = 0
((-80 + 20x) + -1x * (4 + -1x)) = 0
(-80 + 20x + (4 * -1x + -1x * -1x)) = 0
(-80 + 20x + (-4x + 1x2)) = 0

Combine like terms: 20x + -4x = 16x
(-80 + 16x + 1x2) = 0

Solving
-80 + 16x + 1x2 = 0

Solving for variable 'x'.

Factor a trinomial.
(-20 + -1x)(4 + -1x) = 0

Subproblem 1
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
Subproblem 2
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
Solution
x = {-20, 4}