d^2-2d-8=0

Solution for d^2-2d-8=0 equation:

Simplifying
d2 + -2d + -8 = 0

Reorder the terms:
-8 + -2d + d2 = 0

Solving
-8 + -2d + d2 = 0

Solving for variable 'd'.

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

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

Simplifying
-2 + -1d = 0

Solving
-2 + -1d = 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 + -1d = 0 + 2

Combine like terms: -2 + 2 = 0
0 + -1d = 0 + 2
-1d = 0 + 2

Combine like terms: 0 + 2 = 2
-1d = 2

Divide each side by '-1'.
d = -2

Simplifying
d = -2
Subproblem 2
Set the factor '(4 + -1d)' equal to zero and attempt to solve:

Simplifying
4 + -1d = 0

Solving
4 + -1d = 0

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

Add '-4' to each side of the equation.
4 + -4 + -1d = 0 + -4

Combine like terms: 4 + -4 = 0
0 + -1d = 0 + -4
-1d = 0 + -4

Combine like terms: 0 + -4 = -4
-1d = -4

Divide each side by '-1'.
d = 4

Simplifying
d = 4
Solution
d = {-2, 4}