x^2-4x-126=0

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Solution for x^2-4x-126=0 equation:


Simplifying
x2 + -4x + -126 = 0

Reorder the terms:
-126 + -4x + x2 = 0

Solving
-126 + -4x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '126' to each side of the equation.
-126 + -4x + 126 + x2 = 0 + 126

Reorder the terms:
-126 + 126 + -4x + x2 = 0 + 126

Combine like terms: -126 + 126 = 0
0 + -4x + x2 = 0 + 126
-4x + x2 = 0 + 126

Combine like terms: 0 + 126 = 126
-4x + x2 = 126

The x term is -4x.  Take half its coefficient (-2).
Square it (4) and add it to both sides.

Add '4' to each side of the equation.
-4x + 4 + x2 = 126 + 4

Reorder the terms:
4 + -4x + x2 = 126 + 4

Combine like terms: 126 + 4 = 130
4 + -4x + x2 = 130

Factor a perfect square on the left side:
(x + -2)(x + -2) = 130

Calculate the square root of the right side: 11.401754251

Break this problem into two subproblems by setting 
(x + -2) equal to 11.401754251 and -11.401754251.

Subproblem 1

x + -2 = 11.401754251 Simplifying x + -2 = 11.401754251 Reorder the terms: -2 + x = 11.401754251 Solving -2 + x = 11.401754251 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '2' to each side of the equation. -2 + 2 + x = 11.401754251 + 2 Combine like terms: -2 + 2 = 0 0 + x = 11.401754251 + 2 x = 11.401754251 + 2 Combine like terms: 11.401754251 + 2 = 13.401754251 x = 13.401754251 Simplifying x = 13.401754251

Subproblem 2

x + -2 = -11.401754251 Simplifying x + -2 = -11.401754251 Reorder the terms: -2 + x = -11.401754251 Solving -2 + x = -11.401754251 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '2' to each side of the equation. -2 + 2 + x = -11.401754251 + 2 Combine like terms: -2 + 2 = 0 0 + x = -11.401754251 + 2 x = -11.401754251 + 2 Combine like terms: -11.401754251 + 2 = -9.401754251 x = -9.401754251 Simplifying x = -9.401754251

Solution

The solution to the problem is based on the solutions from the subproblems. x = {13.401754251, -9.401754251}

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