3x^2+18x+13=0

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Solution for 3x^2+18x+13=0 equation:


Simplifying
3x2 + 18x + 13 = 0

Reorder the terms:
13 + 18x + 3x2 = 0

Solving
13 + 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'.
4.333333333 + 6x + x2 = 0

Move the constant term to the right:

Add '-4.333333333' to each side of the equation.
4.333333333 + 6x + -4.333333333 + x2 = 0 + -4.333333333

Reorder the terms:
4.333333333 + -4.333333333 + 6x + x2 = 0 + -4.333333333

Combine like terms: 4.333333333 + -4.333333333 = 0.000000000
0.000000000 + 6x + x2 = 0 + -4.333333333
6x + x2 = 0 + -4.333333333

Combine like terms: 0 + -4.333333333 = -4.333333333
6x + x2 = -4.333333333

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 = -4.333333333 + 9

Reorder the terms:
9 + 6x + x2 = -4.333333333 + 9

Combine like terms: -4.333333333 + 9 = 4.666666667
9 + 6x + x2 = 4.666666667

Factor a perfect square on the left side:
(x + 3)(x + 3) = 4.666666667

Calculate the square root of the right side: 2.1602469

Break this problem into two subproblems by setting 
(x + 3) equal to 2.1602469 and -2.1602469.

Subproblem 1

x + 3 = 2.1602469 Simplifying x + 3 = 2.1602469 Reorder the terms: 3 + x = 2.1602469 Solving 3 + x = 2.1602469 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 = 2.1602469 + -3 Combine like terms: 3 + -3 = 0 0 + x = 2.1602469 + -3 x = 2.1602469 + -3 Combine like terms: 2.1602469 + -3 = -0.8397531 x = -0.8397531 Simplifying x = -0.8397531

Subproblem 2

x + 3 = -2.1602469 Simplifying x + 3 = -2.1602469 Reorder the terms: 3 + x = -2.1602469 Solving 3 + x = -2.1602469 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 = -2.1602469 + -3 Combine like terms: 3 + -3 = 0 0 + x = -2.1602469 + -3 x = -2.1602469 + -3 Combine like terms: -2.1602469 + -3 = -5.1602469 x = -5.1602469 Simplifying x = -5.1602469

Solution

The solution to the problem is based on the solutions from the subproblems. x = {-0.8397531, -5.1602469}

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