d^2+7d+9=0

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Solution for d^2+7d+9=0 equation:


Simplifying
d2 + 7d + 9 = 0

Reorder the terms:
9 + 7d + d2 = 0

Solving
9 + 7d + d2 = 0

Solving for variable 'd'.

Begin completing the square.

Move the constant term to the right:

Add '-9' to each side of the equation.
9 + 7d + -9 + d2 = 0 + -9

Reorder the terms:
9 + -9 + 7d + d2 = 0 + -9

Combine like terms: 9 + -9 = 0
0 + 7d + d2 = 0 + -9
7d + d2 = 0 + -9

Combine like terms: 0 + -9 = -9
7d + d2 = -9

The d term is 7d.  Take half its coefficient (3.5).
Square it (12.25) and add it to both sides.

Add '12.25' to each side of the equation.
7d + 12.25 + d2 = -9 + 12.25

Reorder the terms:
12.25 + 7d + d2 = -9 + 12.25

Combine like terms: -9 + 12.25 = 3.25
12.25 + 7d + d2 = 3.25

Factor a perfect square on the left side:
(d + 3.5)(d + 3.5) = 3.25

Calculate the square root of the right side: 1.802775638

Break this problem into two subproblems by setting 
(d + 3.5) equal to 1.802775638 and -1.802775638.

Subproblem 1

d + 3.5 = 1.802775638 Simplifying d + 3.5 = 1.802775638 Reorder the terms: 3.5 + d = 1.802775638 Solving 3.5 + d = 1.802775638 Solving for variable 'd'. Move all terms containing d to the left, all other terms to the right. Add '-3.5' to each side of the equation. 3.5 + -3.5 + d = 1.802775638 + -3.5 Combine like terms: 3.5 + -3.5 = 0.0 0.0 + d = 1.802775638 + -3.5 d = 1.802775638 + -3.5 Combine like terms: 1.802775638 + -3.5 = -1.697224362 d = -1.697224362 Simplifying d = -1.697224362

Subproblem 2

d + 3.5 = -1.802775638 Simplifying d + 3.5 = -1.802775638 Reorder the terms: 3.5 + d = -1.802775638 Solving 3.5 + d = -1.802775638 Solving for variable 'd'. Move all terms containing d to the left, all other terms to the right. Add '-3.5' to each side of the equation. 3.5 + -3.5 + d = -1.802775638 + -3.5 Combine like terms: 3.5 + -3.5 = 0.0 0.0 + d = -1.802775638 + -3.5 d = -1.802775638 + -3.5 Combine like terms: -1.802775638 + -3.5 = -5.302775638 d = -5.302775638 Simplifying d = -5.302775638

Solution

The solution to the problem is based on the solutions from the subproblems. d = {-1.697224362, -5.302775638}

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