21b^2-114b-72=0

Solution for 21b^2-114b-72=0 equation:

Simplifying
21b2 + -114b + -72 = 0

Reorder the terms:
-72 + -114b + 21b2 = 0

Solving
-72 + -114b + 21b2 = 0

Solving for variable 'b'.

Factor out the Greatest Common Factor (GCF), '3'.
3(-24 + -38b + 7b2) = 0

Factor a trinomial.
3((-4 + -7b)(6 + -1b)) = 0

Ignore the factor 3.
Subproblem 1
Set the factor '(-4 + -7b)' equal to zero and attempt to solve:

Simplifying
-4 + -7b = 0

Solving
-4 + -7b = 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 + -7b = 0 + 4

Combine like terms: -4 + 4 = 0
0 + -7b = 0 + 4
-7b = 0 + 4

Combine like terms: 0 + 4 = 4
-7b = 4

Divide each side by '-7'.
b = -0.5714285714

Simplifying
b = -0.5714285714
Subproblem 2
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
Solution
b = {-0.5714285714, 6}