9b^2+21b-8=0

Solution for 9b^2+21b-8=0 equation:

Simplifying
9b2 + 21b + -8 = 0

Reorder the terms:
-8 + 21b + 9b2 = 0

Solving
-8 + 21b + 9b2 = 0

Solving for variable 'b'.

Factor a trinomial.
(-8 + -3b)(1 + -3b) = 0

Subproblem 1
Set the factor '(-8 + -3b)' equal to zero and attempt to solve:

Simplifying
-8 + -3b = 0

Solving
-8 + -3b = 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 + -3b = 0 + 8

Combine like terms: -8 + 8 = 0
0 + -3b = 0 + 8
-3b = 0 + 8

Combine like terms: 0 + 8 = 8
-3b = 8

Divide each side by '-3'.
b = -2.666666667

Simplifying
b = -2.666666667
Subproblem 2
Set the factor '(1 + -3b)' equal to zero and attempt to solve:

Simplifying
1 + -3b = 0

Solving
1 + -3b = 0

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

Add '-1' to each side of the equation.
1 + -1 + -3b = 0 + -1

Combine like terms: 1 + -1 = 0
0 + -3b = 0 + -1
-3b = 0 + -1

Combine like terms: 0 + -1 = -1
-3b = -1

Divide each side by '-3'.
b = 0.3333333333

Simplifying
b = 0.3333333333
Solution
b = {-2.666666667, 0.3333333333}