b^2+8b=-15

Solution for b^2+8b=-15 equation:

Simplifying
b2 + 8b = -15

Reorder the terms:
8b + b2 = -15

Solving
8b + b2 = -15

Solving for variable 'b'.

Reorder the terms:
15 + 8b + b2 = -15 + 15

Combine like terms: -15 + 15 = 0
15 + 8b + b2 = 0

Factor a trinomial.
(5 + b)(3 + 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 '(3 + b)' equal to zero and attempt to solve:

Simplifying
3 + b = 0

Solving
3 + b = 0

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

Add '-3' to each side of the equation.
3 + -3 + b = 0 + -3

Combine like terms: 3 + -3 = 0
0 + b = 0 + -3
b = 0 + -3

Combine like terms: 0 + -3 = -3
b = -3

Simplifying
b = -3
Solution
b = {-5, -3}