x(x+4)=-20

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

Simplifying
x(x + 4) = -20

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

Solving
4x + x2 = -20

Solving for variable 'x'.

Reorder the terms:
20 + 4x + x2 = -20 + 20

Combine like terms: -20 + 20 = 0
20 + 4x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-20' to each side of the equation.
20 + 4x + -20 + x2 = 0 + -20

Reorder the terms:
20 + -20 + 4x + x2 = 0 + -20

Combine like terms: 20 + -20 = 0
0 + 4x + x2 = 0 + -20
4x + x2 = 0 + -20

Combine like terms: 0 + -20 = -20
4x + x2 = -20

The x term is 4x.  Take half its coefficient (2).
Square it (4) and add it to both sides.

Add '4' to each side of the equation.
4x + 4 + x2 = -20 + 4

Reorder the terms:
4 + 4x + x2 = -20 + 4

Combine like terms: -20 + 4 = -16
4 + 4x + x2 = -16

Factor a perfect square on the left side:
(x + 2)(x + 2) = -16

Can't calculate square root of the right side.

The solution to this equation could not be determined.