b^2-21b+108=

Solution for b^2-21b+108= equation:

Simplifying
b2 + -21b + 108 = 0

Reorder the terms:
108 + -21b + b2 = 0

Solving
108 + -21b + b2 = 0

Solving for variable 'b'.

Factor a trinomial.
(9 + -1b)(12 + -1b) = 0

Subproblem 1
Set the factor '(9 + -1b)' equal to zero and attempt to solve:

Simplifying
9 + -1b = 0

Solving
9 + -1b = 0

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

Add '-9' to each side of the equation.
9 + -9 + -1b = 0 + -9

Combine like terms: 9 + -9 = 0
0 + -1b = 0 + -9
-1b = 0 + -9

Combine like terms: 0 + -9 = -9
-1b = -9

Divide each side by '-1'.
b = 9

Simplifying
b = 9
Subproblem 2
Set the factor '(12 + -1b)' equal to zero and attempt to solve:

Simplifying
12 + -1b = 0

Solving
12 + -1b = 0

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

Add '-12' to each side of the equation.
12 + -12 + -1b = 0 + -12

Combine like terms: 12 + -12 = 0
0 + -1b = 0 + -12
-1b = 0 + -12

Combine like terms: 0 + -12 = -12
-1b = -12

Divide each side by '-1'.
b = 12

Simplifying
b = 12
Solution
b = {9, 12}