0.5D^2+1.5D+1=0

Solution for 0.5D^2+1.5D+1=0 equation:

Simplifying
0.5D2 + 1.5D + 1 = 0

Reorder the terms:
1 + 1.5D + 0.5D2 = 0

Solving
1 + 1.5D + 0.5D2 = 0

Solving for variable 'D'.

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

Divide each side by '0.5'.
2 + 3D + D2 = 0

Move the constant term to the right:

Add '-2' to each side of the equation.
2 + 3D + -2 + D2 = 0 + -2

Reorder the terms:
2 + -2 + 3D + D2 = 0 + -2

Combine like terms: 2 + -2 = 0
0 + 3D + D2 = 0 + -2
3D + D2 = 0 + -2

Combine like terms: 0 + -2 = -2
3D + D2 = -2

The D term is 3D.  Take half its coefficient (1.5).
Square it (2.25) and add it to both sides.

Add '2.25' to each side of the equation.
3D + 2.25 + D2 = -2 + 2.25

Reorder the terms:
2.25 + 3D + D2 = -2 + 2.25

Combine like terms: -2 + 2.25 = 0.25
2.25 + 3D + D2 = 0.25

Factor a perfect square on the left side:
(D + 1.5)(D + 1.5) = 0.25

Calculate the square root of the right side: 0.5

Break this problem into two subproblems by setting 
(D + 1.5) equal to 0.5 and -0.5.

Subproblem 1
D + 1.5 = 0.5

Simplifying
D + 1.5 = 0.5

Reorder the terms:
1.5 + D = 0.5

Solving
1.5 + D = 0.5

Solving for variable 'D'.

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

Add '-1.5' to each side of the equation.
1.5 + -1.5 + D = 0.5 + -1.5

Combine like terms: 1.5 + -1.5 = 0.0
0.0 + D = 0.5 + -1.5
D = 0.5 + -1.5

Combine like terms: 0.5 + -1.5 = -1
D = -1

Simplifying
D = -1

Subproblem 2
D + 1.5 = -0.5

Simplifying
D + 1.5 = -0.5

Reorder the terms:
1.5 + D = -0.5

Solving
1.5 + D = -0.5

Solving for variable 'D'.

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

Add '-1.5' to each side of the equation.
1.5 + -1.5 + D = -0.5 + -1.5

Combine like terms: 1.5 + -1.5 = 0.0
0.0 + D = -0.5 + -1.5
D = -0.5 + -1.5

Combine like terms: -0.5 + -1.5 = -2
D = -2

Simplifying
D = -2

Solution
The solution to the problem is based on the solutions
from the subproblems.
D = {-1, -2}