-5x(x+3)=-20

Solution for -5x(x+3)=-20 equation:

Simplifying
-5x(x + 3) = -20

Reorder the terms:
-5x(3 + x) = -20
(3 * -5x + x * -5x) = -20
(-15x + -5x2) = -20

Solving
-15x + -5x2 = -20

Solving for variable 'x'.

Reorder the terms:
20 + -15x + -5x2 = -20 + 20

Combine like terms: -20 + 20 = 0
20 + -15x + -5x2 = 0

Factor out the Greatest Common Factor (GCF), '5'.
5(4 + -3x + -1x2) = 0

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

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

Simplifying
1 + -1x = 0

Solving
1 + -1x = 0

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

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

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

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

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

Simplifying
x = 1
Subproblem 2
Set the factor '(4 + x)' equal to zero and attempt to solve:

Simplifying
4 + x = 0

Solving
4 + x = 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 + x = 0 + -4

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

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

Simplifying
x = -4
Solution
x = {1, -4}