d^2-4d-6=0

Solution for d^2-4d-6=0 equation:

Simplifying
d2 + -4d + -6 = 0

Reorder the terms:
-6 + -4d + d2 = 0

Solving
-6 + -4d + d2 = 0

Solving for variable 'd'.

Begin completing the square.

Move the constant term to the right:

Add '6' to each side of the equation.
-6 + -4d + 6 + d2 = 0 + 6

Reorder the terms:
-6 + 6 + -4d + d2 = 0 + 6

Combine like terms: -6 + 6 = 0
0 + -4d + d2 = 0 + 6
-4d + d2 = 0 + 6

Combine like terms: 0 + 6 = 6
-4d + d2 = 6

The d term is -4d.  Take half its coefficient (-2).
Square it (4) and add it to both sides.

Add '4' to each side of the equation.
-4d + 4 + d2 = 6 + 4

Reorder the terms:
4 + -4d + d2 = 6 + 4

Combine like terms: 6 + 4 = 10
4 + -4d + d2 = 10

Factor a perfect square on the left side:
(d + -2)(d + -2) = 10

Calculate the square root of the right side: 3.16227766

Break this problem into two subproblems by setting 
(d + -2) equal to 3.16227766 and -3.16227766.

Subproblem 1
d + -2 = 3.16227766

Simplifying
d + -2 = 3.16227766

Reorder the terms:
-2 + d = 3.16227766

Solving
-2 + d = 3.16227766

Solving for variable 'd'.

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

Add '2' to each side of the equation.
-2 + 2 + d = 3.16227766 + 2

Combine like terms: -2 + 2 = 0
0 + d = 3.16227766 + 2
d = 3.16227766 + 2

Combine like terms: 3.16227766 + 2 = 5.16227766
d = 5.16227766

Simplifying
d = 5.16227766

Subproblem 2
d + -2 = -3.16227766

Simplifying
d + -2 = -3.16227766

Reorder the terms:
-2 + d = -3.16227766

Solving
-2 + d = -3.16227766

Solving for variable 'd'.

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

Add '2' to each side of the equation.
-2 + 2 + d = -3.16227766 + 2

Combine like terms: -2 + 2 = 0
0 + d = -3.16227766 + 2
d = -3.16227766 + 2

Combine like terms: -3.16227766 + 2 = -1.16227766
d = -1.16227766

Simplifying
d = -1.16227766

Solution
The solution to the problem is based on the solutions
from the subproblems.
d = {5.16227766, -1.16227766}