6x^2-8x-15=0

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Solution for 6x^2-8x-15=0 equation:


Simplifying
6x2 + -8x + -15 = 0

Reorder the terms:
-15 + -8x + 6x2 = 0

Solving
-15 + -8x + 6x2 = 0

Solving for variable 'x'.

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

Divide each side by '6'.
-2.5 + -1.333333333x + x2 = 0

Move the constant term to the right:

Add '2.5' to each side of the equation.
-2.5 + -1.333333333x + 2.5 + x2 = 0 + 2.5

Reorder the terms:
-2.5 + 2.5 + -1.333333333x + x2 = 0 + 2.5

Combine like terms: -2.5 + 2.5 = 0.0
0.0 + -1.333333333x + x2 = 0 + 2.5
-1.333333333x + x2 = 0 + 2.5

Combine like terms: 0 + 2.5 = 2.5
-1.333333333x + x2 = 2.5

The x term is -1.333333333x.  Take half its coefficient (-0.6666666665).
Square it (0.4444444442) and add it to both sides.

Add '0.4444444442' to each side of the equation.
-1.333333333x + 0.4444444442 + x2 = 2.5 + 0.4444444442

Reorder the terms:
0.4444444442 + -1.333333333x + x2 = 2.5 + 0.4444444442

Combine like terms: 2.5 + 0.4444444442 = 2.9444444442
0.4444444442 + -1.333333333x + x2 = 2.9444444442

Factor a perfect square on the left side:
(x + -0.6666666665)(x + -0.6666666665) = 2.9444444442

Calculate the square root of the right side: 1.715938357

Break this problem into two subproblems by setting 
(x + -0.6666666665) equal to 1.715938357 and -1.715938357.

Subproblem 1

x + -0.6666666665 = 1.715938357 Simplifying x + -0.6666666665 = 1.715938357 Reorder the terms: -0.6666666665 + x = 1.715938357 Solving -0.6666666665 + x = 1.715938357 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.6666666665' to each side of the equation. -0.6666666665 + 0.6666666665 + x = 1.715938357 + 0.6666666665 Combine like terms: -0.6666666665 + 0.6666666665 = 0.0000000000 0.0000000000 + x = 1.715938357 + 0.6666666665 x = 1.715938357 + 0.6666666665 Combine like terms: 1.715938357 + 0.6666666665 = 2.3826050235 x = 2.3826050235 Simplifying x = 2.3826050235

Subproblem 2

x + -0.6666666665 = -1.715938357 Simplifying x + -0.6666666665 = -1.715938357 Reorder the terms: -0.6666666665 + x = -1.715938357 Solving -0.6666666665 + x = -1.715938357 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.6666666665' to each side of the equation. -0.6666666665 + 0.6666666665 + x = -1.715938357 + 0.6666666665 Combine like terms: -0.6666666665 + 0.6666666665 = 0.0000000000 0.0000000000 + x = -1.715938357 + 0.6666666665 x = -1.715938357 + 0.6666666665 Combine like terms: -1.715938357 + 0.6666666665 = -1.0492716905 x = -1.0492716905 Simplifying x = -1.0492716905

Solution

The solution to the problem is based on the solutions from the subproblems. x = {2.3826050235, -1.0492716905}

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