4b^2+21b+20=

Solution for 4b^2+21b+20= equation:

Simplifying
4b2 + 21b + 20 = 0

Reorder the terms:
20 + 21b + 4b2 = 0

Solving
20 + 21b + 4b2 = 0

Solving for variable 'b'.

Factor a trinomial.
(4 + b)(5 + 4b) = 0

Subproblem 1
Set the factor '(4 + b)' equal to zero and attempt to solve:

Simplifying
4 + b = 0

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

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

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

Simplifying
b = -4
Subproblem 2
Set the factor '(5 + 4b)' equal to zero and attempt to solve:

Simplifying
5 + 4b = 0

Solving
5 + 4b = 0

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

Add '-5' to each side of the equation.
5 + -5 + 4b = 0 + -5

Combine like terms: 5 + -5 = 0
0 + 4b = 0 + -5
4b = 0 + -5

Combine like terms: 0 + -5 = -5
4b = -5

Divide each side by '4'.
b = -1.25

Simplifying
b = -1.25
Solution
b = {-4, -1.25}