7x^2-20x-5=0

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Solution for 7x^2-20x-5=0 equation:


Simplifying
7x2 + -20x + -5 = 0

Reorder the terms:
-5 + -20x + 7x2 = 0

Solving
-5 + -20x + 7x2 = 0

Solving for variable 'x'.

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

Divide each side by '7'.
-0.7142857143 + -2.857142857x + x2 = 0

Move the constant term to the right:

Add '0.7142857143' to each side of the equation.
-0.7142857143 + -2.857142857x + 0.7142857143 + x2 = 0 + 0.7142857143

Reorder the terms:
-0.7142857143 + 0.7142857143 + -2.857142857x + x2 = 0 + 0.7142857143

Combine like terms: -0.7142857143 + 0.7142857143 = 0.0000000000
0.0000000000 + -2.857142857x + x2 = 0 + 0.7142857143
-2.857142857x + x2 = 0 + 0.7142857143

Combine like terms: 0 + 0.7142857143 = 0.7142857143
-2.857142857x + x2 = 0.7142857143

The x term is -2.857142857x.  Take half its coefficient (-1.428571429).
Square it (2.040816328) and add it to both sides.

Add '2.040816328' to each side of the equation.
-2.857142857x + 2.040816328 + x2 = 0.7142857143 + 2.040816328

Reorder the terms:
2.040816328 + -2.857142857x + x2 = 0.7142857143 + 2.040816328

Combine like terms: 0.7142857143 + 2.040816328 = 2.7551020423
2.040816328 + -2.857142857x + x2 = 2.7551020423

Factor a perfect square on the left side:
(x + -1.428571429)(x + -1.428571429) = 2.7551020423

Calculate the square root of the right side: 1.659850006

Break this problem into two subproblems by setting 
(x + -1.428571429) equal to 1.659850006 and -1.659850006.

Subproblem 1

x + -1.428571429 = 1.659850006 Simplifying x + -1.428571429 = 1.659850006 Reorder the terms: -1.428571429 + x = 1.659850006 Solving -1.428571429 + x = 1.659850006 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.428571429' to each side of the equation. -1.428571429 + 1.428571429 + x = 1.659850006 + 1.428571429 Combine like terms: -1.428571429 + 1.428571429 = 0.000000000 0.000000000 + x = 1.659850006 + 1.428571429 x = 1.659850006 + 1.428571429 Combine like terms: 1.659850006 + 1.428571429 = 3.088421435 x = 3.088421435 Simplifying x = 3.088421435

Subproblem 2

x + -1.428571429 = -1.659850006 Simplifying x + -1.428571429 = -1.659850006 Reorder the terms: -1.428571429 + x = -1.659850006 Solving -1.428571429 + x = -1.659850006 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.428571429' to each side of the equation. -1.428571429 + 1.428571429 + x = -1.659850006 + 1.428571429 Combine like terms: -1.428571429 + 1.428571429 = 0.000000000 0.000000000 + x = -1.659850006 + 1.428571429 x = -1.659850006 + 1.428571429 Combine like terms: -1.659850006 + 1.428571429 = -0.231278577 x = -0.231278577 Simplifying x = -0.231278577

Solution

The solution to the problem is based on the solutions from the subproblems. x = {3.088421435, -0.231278577}

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