3d^2-5d-8=0

Solution for 3d^2-5d-8=0 equation:

Simplifying
3d2 + -5d + -8 = 0

Reorder the terms:
-8 + -5d + 3d2 = 0

Solving
-8 + -5d + 3d2 = 0

Solving for variable 'd'.

Factor a trinomial.
(-1 + -1d)(8 + -3d) = 0

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

Simplifying
-1 + -1d = 0

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

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

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

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

Simplifying
d = -1
Subproblem 2
Set the factor '(8 + -3d)' equal to zero and attempt to solve:

Simplifying
8 + -3d = 0

Solving
8 + -3d = 0

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

Add '-8' to each side of the equation.
8 + -8 + -3d = 0 + -8

Combine like terms: 8 + -8 = 0
0 + -3d = 0 + -8
-3d = 0 + -8

Combine like terms: 0 + -8 = -8
-3d = -8

Divide each side by '-3'.
d = 2.666666667

Simplifying
d = 2.666666667
Solution
d = {-1, 2.666666667}