3x^2+40x-99=0

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Solution for 3x^2+40x-99=0 equation:


Simplifying
3x2 + 40x + -99 = 0

Reorder the terms:
-99 + 40x + 3x2 = 0

Solving
-99 + 40x + 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'.
-33 + 13.33333333x + x2 = 0

Move the constant term to the right:

Add '33' to each side of the equation.
-33 + 13.33333333x + 33 + x2 = 0 + 33

Reorder the terms:
-33 + 33 + 13.33333333x + x2 = 0 + 33

Combine like terms: -33 + 33 = 0
0 + 13.33333333x + x2 = 0 + 33
13.33333333x + x2 = 0 + 33

Combine like terms: 0 + 33 = 33
13.33333333x + x2 = 33

The x term is 13.33333333x.  Take half its coefficient (6.666666665).
Square it (44.44444442) and add it to both sides.

Add '44.44444442' to each side of the equation.
13.33333333x + 44.44444442 + x2 = 33 + 44.44444442

Reorder the terms:
44.44444442 + 13.33333333x + x2 = 33 + 44.44444442

Combine like terms: 33 + 44.44444442 = 77.44444442
44.44444442 + 13.33333333x + x2 = 77.44444442

Factor a perfect square on the left side:
(x + 6.666666665)(x + 6.666666665) = 77.44444442

Calculate the square root of the right side: 8.80025252

Break this problem into two subproblems by setting 
(x + 6.666666665) equal to 8.80025252 and -8.80025252.

Subproblem 1

x + 6.666666665 = 8.80025252 Simplifying x + 6.666666665 = 8.80025252 Reorder the terms: 6.666666665 + x = 8.80025252 Solving 6.666666665 + x = 8.80025252 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-6.666666665' to each side of the equation. 6.666666665 + -6.666666665 + x = 8.80025252 + -6.666666665 Combine like terms: 6.666666665 + -6.666666665 = 0.000000000 0.000000000 + x = 8.80025252 + -6.666666665 x = 8.80025252 + -6.666666665 Combine like terms: 8.80025252 + -6.666666665 = 2.133585855 x = 2.133585855 Simplifying x = 2.133585855

Subproblem 2

x + 6.666666665 = -8.80025252 Simplifying x + 6.666666665 = -8.80025252 Reorder the terms: 6.666666665 + x = -8.80025252 Solving 6.666666665 + x = -8.80025252 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-6.666666665' to each side of the equation. 6.666666665 + -6.666666665 + x = -8.80025252 + -6.666666665 Combine like terms: 6.666666665 + -6.666666665 = 0.000000000 0.000000000 + x = -8.80025252 + -6.666666665 x = -8.80025252 + -6.666666665 Combine like terms: -8.80025252 + -6.666666665 = -15.466919185 x = -15.466919185 Simplifying x = -15.466919185

Solution

The solution to the problem is based on the solutions from the subproblems. x = {2.133585855, -15.466919185}

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