0=-3d^2-6d-2

Solution for 0=-3d^2-6d-2 equation:

Simplifying
0 = -3d2 + -6d + -2

Reorder the terms:
0 = -2 + -6d + -3d2

Solving
0 = -2 + -6d + -3d2

Solving for variable 'd'.

Combine like terms: 0 + 2 = 2
2 + 6d + 3d2 = -2 + -6d + -3d2 + 2 + 6d + 3d2

Reorder the terms:
2 + 6d + 3d2 = -2 + 2 + -6d + 6d + -3d2 + 3d2

Combine like terms: -2 + 2 = 0
2 + 6d + 3d2 = 0 + -6d + 6d + -3d2 + 3d2
2 + 6d + 3d2 = -6d + 6d + -3d2 + 3d2

Combine like terms: -6d + 6d = 0
2 + 6d + 3d2 = 0 + -3d2 + 3d2
2 + 6d + 3d2 = -3d2 + 3d2

Combine like terms: -3d2 + 3d2 = 0
2 + 6d + 3d2 = 0

Begin completing the square.  Divide all terms by
3 the coefficient of the squared term: 

Divide each side by '3'.
0.6666666667 + 2d + d2 = 0

Move the constant term to the right:

Add '-0.6666666667' to each side of the equation.
0.6666666667 + 2d + -0.6666666667 + d2 = 0 + -0.6666666667

Reorder the terms:
0.6666666667 + -0.6666666667 + 2d + d2 = 0 + -0.6666666667

Combine like terms: 0.6666666667 + -0.6666666667 = 0.0000000000
0.0000000000 + 2d + d2 = 0 + -0.6666666667
2d + d2 = 0 + -0.6666666667

Combine like terms: 0 + -0.6666666667 = -0.6666666667
2d + d2 = -0.6666666667

The d term is 2d.  Take half its coefficient (1).
Square it (1) and add it to both sides.

Add '1' to each side of the equation.
2d + 1 + d2 = -0.6666666667 + 1

Reorder the terms:
1 + 2d + d2 = -0.6666666667 + 1

Combine like terms: -0.6666666667 + 1 = 0.3333333333
1 + 2d + d2 = 0.3333333333

Factor a perfect square on the left side:
(d + 1)(d + 1) = 0.3333333333

Calculate the square root of the right side: 0.577350269

Break this problem into two subproblems by setting 
(d + 1) equal to 0.577350269 and -0.577350269.

Subproblem 1
d + 1 = 0.577350269

Simplifying
d + 1 = 0.577350269

Reorder the terms:
1 + d = 0.577350269

Solving
1 + d = 0.577350269

Solving for variable 'd'.

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 = 0.577350269 + -1

Combine like terms: 1 + -1 = 0
0 + d = 0.577350269 + -1
d = 0.577350269 + -1

Combine like terms: 0.577350269 + -1 = -0.422649731
d = -0.422649731

Simplifying
d = -0.422649731

Subproblem 2
d + 1 = -0.577350269

Simplifying
d + 1 = -0.577350269

Reorder the terms:
1 + d = -0.577350269

Solving
1 + d = -0.577350269

Solving for variable 'd'.

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 = -0.577350269 + -1

Combine like terms: 1 + -1 = 0
0 + d = -0.577350269 + -1
d = -0.577350269 + -1

Combine like terms: -0.577350269 + -1 = -1.577350269
d = -1.577350269

Simplifying
d = -1.577350269

Solution
The solution to the problem is based on the solutions
from the subproblems.
d = {-0.422649731, -1.577350269}