20b^2-4b-16=0

Solution for 20b^2-4b-16=0 equation:

Simplifying
20b2 + -4b + -16 = 0

Reorder the terms:
-16 + -4b + 20b2 = 0

Solving
-16 + -4b + 20b2 = 0

Solving for variable 'b'.

Factor out the Greatest Common Factor (GCF), '4'.
4(-4 + -1b + 5b2) = 0

Factor a trinomial.
4((-4 + -5b)(1 + -1b)) = 0

Ignore the factor 4.
Subproblem 1
Set the factor '(-4 + -5b)' equal to zero and attempt to solve:

Simplifying
-4 + -5b = 0

Solving
-4 + -5b = 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 + -5b = 0 + 4

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

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

Divide each side by '-5'.
b = -0.8

Simplifying
b = -0.8
Subproblem 2
Set the factor '(1 + -1b)' equal to zero and attempt to solve:

Simplifying
1 + -1b = 0

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

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

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

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

Simplifying
b = 1
Solution
b = {-0.8, 1}