b^2+9b=-20

Solution for b^2+9b=-20 equation:

Simplifying
b2 + 9b = -20

Reorder the terms:
9b + b2 = -20

Solving
9b + b2 = -20

Solving for variable 'b'.

Reorder the terms:
20 + 9b + b2 = -20 + 20

Combine like terms: -20 + 20 = 0
20 + 9b + b2 = 0

Factor a trinomial.
(5 + b)(4 + b) = 0

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

Simplifying
5 + b = 0

Solving
5 + b = 0

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

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

Combine like terms: 5 + -5 = 0
0 + b = 0 + -5
b = 0 + -5

Combine like terms: 0 + -5 = -5
b = -5

Simplifying
b = -5
Subproblem 2
Set the factor '(4 + b)' equal to zero and attempt to solve:

Simplifying
4 + b = 0

Solving
4 + b = 0

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

Add '-4' to each side of the equation.
4 + -4 + b = 0 + -4

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

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

Simplifying
b = -4
Solution
b = {-5, -4}