(b+6)(b-15)=0

Solution for (b+6)(b-15)=0 equation:

Simplifying
(b + 6)(b + -15) = 0

Reorder the terms:
(6 + b)(b + -15) = 0

Reorder the terms:
(6 + b)(-15 + b) = 0

Multiply (6 + b) * (-15 + b)
(6(-15 + b) + b(-15 + b)) = 0
((-15 * 6 + b * 6) + b(-15 + b)) = 0
((-90 + 6b) + b(-15 + b)) = 0
(-90 + 6b + (-15 * b + b * b)) = 0
(-90 + 6b + (-15b + b2)) = 0

Combine like terms: 6b + -15b = -9b
(-90 + -9b + b2) = 0

Solving
-90 + -9b + b2 = 0

Solving for variable 'b'.

Factor a trinomial.
(-6 + -1b)(15 + -1b) = 0

Subproblem 1
Set the factor '(-6 + -1b)' equal to zero and attempt to solve:

Simplifying
-6 + -1b = 0

Solving
-6 + -1b = 0

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

Add '6' to each side of the equation.
-6 + 6 + -1b = 0 + 6

Combine like terms: -6 + 6 = 0
0 + -1b = 0 + 6
-1b = 0 + 6

Combine like terms: 0 + 6 = 6
-1b = 6

Divide each side by '-1'.
b = -6

Simplifying
b = -6
Subproblem 2
Set the factor '(15 + -1b)' equal to zero and attempt to solve:

Simplifying
15 + -1b = 0

Solving
15 + -1b = 0

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

Add '-15' to each side of the equation.
15 + -15 + -1b = 0 + -15

Combine like terms: 15 + -15 = 0
0 + -1b = 0 + -15
-1b = 0 + -15

Combine like terms: 0 + -15 = -15
-1b = -15

Divide each side by '-1'.
b = 15

Simplifying
b = 15
Solution
b = {-6, 15}