20d^2+28d+8=0

Solution for 20d^2+28d+8=0 equation:

Simplifying
20d2 + 28d + 8 = 0

Reorder the terms:
8 + 28d + 20d2 = 0

Solving
8 + 28d + 20d2 = 0

Solving for variable 'd'.

Factor out the Greatest Common Factor (GCF), '4'.
4(2 + 7d + 5d2) = 0

Factor a trinomial.
4((1 + d)(2 + 5d)) = 0

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

Simplifying
1 + d = 0

Solving
1 + d = 0

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

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

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

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

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

Simplifying
2 + 5d = 0

Solving
2 + 5d = 0

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

Add '-2' to each side of the equation.
2 + -2 + 5d = 0 + -2

Combine like terms: 2 + -2 = 0
0 + 5d = 0 + -2
5d = 0 + -2

Combine like terms: 0 + -2 = -2
5d = -2

Divide each side by '5'.
d = -0.4

Simplifying
d = -0.4
Solution
d = {-1, -0.4}