b^2-8b-128=0

Solution for b^2-8b-128=0 equation:

Simplifying
b2 + -8b + -128 = 0

Reorder the terms:
-128 + -8b + b2 = 0

Solving
-128 + -8b + b2 = 0

Solving for variable 'b'.

Factor a trinomial.
(-8 + -1b)(16 + -1b) = 0

Subproblem 1
Set the factor '(-8 + -1b)' equal to zero and attempt to solve:

Simplifying
-8 + -1b = 0

Solving
-8 + -1b = 0

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

Add '8' to each side of the equation.
-8 + 8 + -1b = 0 + 8

Combine like terms: -8 + 8 = 0
0 + -1b = 0 + 8
-1b = 0 + 8

Combine like terms: 0 + 8 = 8
-1b = 8

Divide each side by '-1'.
b = -8

Simplifying
b = -8
Subproblem 2
Set the factor '(16 + -1b)' equal to zero and attempt to solve:

Simplifying
16 + -1b = 0

Solving
16 + -1b = 0

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

Add '-16' to each side of the equation.
16 + -16 + -1b = 0 + -16

Combine like terms: 16 + -16 = 0
0 + -1b = 0 + -16
-1b = 0 + -16

Combine like terms: 0 + -16 = -16
-1b = -16

Divide each side by '-1'.
b = 16

Simplifying
b = 16
Solution
b = {-8, 16}