(x-4)(5x+2)=0

Solution for (x-4)(5x+2)=0 equation:

Simplifying
(x + -4)(5x + 2) = 0

Reorder the terms:
(-4 + x)(5x + 2) = 0

Reorder the terms:
(-4 + x)(2 + 5x) = 0

Multiply (-4 + x) * (2 + 5x)
(-4(2 + 5x) + x(2 + 5x)) = 0
((2 * -4 + 5x * -4) + x(2 + 5x)) = 0
((-8 + -20x) + x(2 + 5x)) = 0
(-8 + -20x + (2 * x + 5x * x)) = 0
(-8 + -20x + (2x + 5x2)) = 0

Combine like terms: -20x + 2x = -18x
(-8 + -18x + 5x2) = 0

Solving
-8 + -18x + 5x2 = 0

Solving for variable 'x'.

Factor a trinomial.
(-2 + -5x)(4 + -1x) = 0

Subproblem 1
Set the factor '(-2 + -5x)' equal to zero and attempt to solve:

Simplifying
-2 + -5x = 0

Solving
-2 + -5x = 0

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

Add '2' to each side of the equation.
-2 + 2 + -5x = 0 + 2

Combine like terms: -2 + 2 = 0
0 + -5x = 0 + 2
-5x = 0 + 2

Combine like terms: 0 + 2 = 2
-5x = 2

Divide each side by '-5'.
x = -0.4

Simplifying
x = -0.4
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 = {-0.4, 4}