-15b^2+102b+21=

Solution for -15b^2+102b+21= equation:

Simplifying
-15b2 + 102b + 21 = 0

Reorder the terms:
21 + 102b + -15b2 = 0

Solving
21 + 102b + -15b2 = 0

Solving for variable 'b'.

Factor out the Greatest Common Factor (GCF), '3'.
3(7 + 34b + -5b2) = 0

Factor a trinomial.
3((7 + -1b)(1 + 5b)) = 0

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

Simplifying
7 + -1b = 0

Solving
7 + -1b = 0

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

Add '-7' to each side of the equation.
7 + -7 + -1b = 0 + -7

Combine like terms: 7 + -7 = 0
0 + -1b = 0 + -7
-1b = 0 + -7

Combine like terms: 0 + -7 = -7
-1b = -7

Divide each side by '-1'.
b = 7

Simplifying
b = 7
Subproblem 2
Set the factor '(1 + 5b)' equal to zero and attempt to solve:

Simplifying
1 + 5b = 0

Solving
1 + 5b = 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 + 5b = 0 + -1

Combine like terms: 1 + -1 = 0
0 + 5b = 0 + -1
5b = 0 + -1

Combine like terms: 0 + -1 = -1
5b = -1

Divide each side by '5'.
b = -0.2

Simplifying
b = -0.2
Solution
b = {7, -0.2}