3*x^2-49*x-21=0

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Solution for 3*x^2-49*x-21=0 equation:


Simplifying
3x2 + -49x + -21 = 0

Reorder the terms:
-21 + -49x + 3x2 = 0

Solving
-21 + -49x + 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'.
-7 + -16.33333333x + x2 = 0

Move the constant term to the right:

Add '7' to each side of the equation.
-7 + -16.33333333x + 7 + x2 = 0 + 7

Reorder the terms:
-7 + 7 + -16.33333333x + x2 = 0 + 7

Combine like terms: -7 + 7 = 0
0 + -16.33333333x + x2 = 0 + 7
-16.33333333x + x2 = 0 + 7

Combine like terms: 0 + 7 = 7
-16.33333333x + x2 = 7

The x term is -16.33333333x.  Take half its coefficient (-8.166666665).
Square it (66.69444442) and add it to both sides.

Add '66.69444442' to each side of the equation.
-16.33333333x + 66.69444442 + x2 = 7 + 66.69444442

Reorder the terms:
66.69444442 + -16.33333333x + x2 = 7 + 66.69444442

Combine like terms: 7 + 66.69444442 = 73.69444442
66.69444442 + -16.33333333x + x2 = 73.69444442

Factor a perfect square on the left side:
(x + -8.166666665)(x + -8.166666665) = 73.69444442

Calculate the square root of the right side: 8.584546838

Break this problem into two subproblems by setting 
(x + -8.166666665) equal to 8.584546838 and -8.584546838.

Subproblem 1

x + -8.166666665 = 8.584546838 Simplifying x + -8.166666665 = 8.584546838 Reorder the terms: -8.166666665 + x = 8.584546838 Solving -8.166666665 + x = 8.584546838 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '8.166666665' to each side of the equation. -8.166666665 + 8.166666665 + x = 8.584546838 + 8.166666665 Combine like terms: -8.166666665 + 8.166666665 = 0.000000000 0.000000000 + x = 8.584546838 + 8.166666665 x = 8.584546838 + 8.166666665 Combine like terms: 8.584546838 + 8.166666665 = 16.751213503 x = 16.751213503 Simplifying x = 16.751213503

Subproblem 2

x + -8.166666665 = -8.584546838 Simplifying x + -8.166666665 = -8.584546838 Reorder the terms: -8.166666665 + x = -8.584546838 Solving -8.166666665 + x = -8.584546838 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '8.166666665' to each side of the equation. -8.166666665 + 8.166666665 + x = -8.584546838 + 8.166666665 Combine like terms: -8.166666665 + 8.166666665 = 0.000000000 0.000000000 + x = -8.584546838 + 8.166666665 x = -8.584546838 + 8.166666665 Combine like terms: -8.584546838 + 8.166666665 = -0.417880173 x = -0.417880173 Simplifying x = -0.417880173

Solution

The solution to the problem is based on the solutions from the subproblems. x = {16.751213503, -0.417880173}

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