3x^2+18x+8=0

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Solution for 3x^2+18x+8=0 equation: 


Simplifying
3x2 + 18x + 8 = 0

Reorder the terms:
8 + 18x + 3x2 = 0

Solving
8 + 18x + 3x2 = 0

Solving for variable 'x'.

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

Divide each side by '3'.
2.666666667 + 6x + x2 = 0

Move the constant term to the right:

Add '-2.666666667' to each side of the equation.
2.666666667 + 6x + -2.666666667 + x2 = 0 + -2.666666667

Reorder the terms:
2.666666667 + -2.666666667 + 6x + x2 = 0 + -2.666666667

Combine like terms: 2.666666667 + -2.666666667 = 0.000000000
0.000000000 + 6x + x2 = 0 + -2.666666667
6x + x2 = 0 + -2.666666667

Combine like terms: 0 + -2.666666667 = -2.666666667
6x + x2 = -2.666666667

The x term is 6x.  Take half its coefficient (3).
Square it (9) and add it to both sides.

Add '9' to each side of the equation.
6x + 9 + x2 = -2.666666667 + 9

Reorder the terms:
9 + 6x + x2 = -2.666666667 + 9

Combine like terms: -2.666666667 + 9 = 6.333333333
9 + 6x + x2 = 6.333333333

Factor a perfect square on the left side:
(x + 3)(x + 3) = 6.333333333

Calculate the square root of the right side: 2.516611478

Break this problem into two subproblems by setting 
(x + 3) equal to 2.516611478 and -2.516611478.


Subproblem 1
x + 3 = 2.516611478

Simplifying
x + 3 = 2.516611478

Reorder the terms:
3 + x = 2.516611478

Solving
3 + x = 2.516611478

Solving for variable 'x'.

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

Add '-3' to each side of the equation.
3 + -3 + x = 2.516611478 + -3

Combine like terms: 3 + -3 = 0
0 + x = 2.516611478 + -3
x = 2.516611478 + -3

Combine like terms: 2.516611478 + -3 = -0.483388522
x = -0.483388522

Simplifying
x = -0.483388522


Subproblem 2
x + 3 = -2.516611478

Simplifying
x + 3 = -2.516611478

Reorder the terms:
3 + x = -2.516611478

Solving
3 + x = -2.516611478

Solving for variable 'x'.

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

Add '-3' to each side of the equation.
3 + -3 + x = -2.516611478 + -3

Combine like terms: 3 + -3 = 0
0 + x = -2.516611478 + -3
x = -2.516611478 + -3

Combine like terms: -2.516611478 + -3 = -5.516611478
x = -5.516611478

Simplifying
x = -5.516611478


Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {-0.483388522, -5.516611478}

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