11x^2-6x-21=0

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Solution for 11x^2-6x-21=0 equation:


Simplifying
11x2 + -6x + -21 = 0

Reorder the terms:
-21 + -6x + 11x2 = 0

Solving
-21 + -6x + 11x2 = 0

Solving for variable 'x'.

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

Divide each side by '11'.
-1.909090909 + -0.5454545455x + x2 = 0

Move the constant term to the right:

Add '1.909090909' to each side of the equation.
-1.909090909 + -0.5454545455x + 1.909090909 + x2 = 0 + 1.909090909

Reorder the terms:
-1.909090909 + 1.909090909 + -0.5454545455x + x2 = 0 + 1.909090909

Combine like terms: -1.909090909 + 1.909090909 = 0.000000000
0.000000000 + -0.5454545455x + x2 = 0 + 1.909090909
-0.5454545455x + x2 = 0 + 1.909090909

Combine like terms: 0 + 1.909090909 = 1.909090909
-0.5454545455x + x2 = 1.909090909

The x term is -0.5454545455x.  Take half its coefficient (-0.2727272728).
Square it (0.07438016533) and add it to both sides.

Add '0.07438016533' to each side of the equation.
-0.5454545455x + 0.07438016533 + x2 = 1.909090909 + 0.07438016533

Reorder the terms:
0.07438016533 + -0.5454545455x + x2 = 1.909090909 + 0.07438016533

Combine like terms: 1.909090909 + 0.07438016533 = 1.98347107433
0.07438016533 + -0.5454545455x + x2 = 1.98347107433

Factor a perfect square on the left side:
(x + -0.2727272728)(x + -0.2727272728) = 1.98347107433

Calculate the square root of the right side: 1.40835758

Break this problem into two subproblems by setting 
(x + -0.2727272728) equal to 1.40835758 and -1.40835758.

Subproblem 1

x + -0.2727272728 = 1.40835758 Simplifying x + -0.2727272728 = 1.40835758 Reorder the terms: -0.2727272728 + x = 1.40835758 Solving -0.2727272728 + x = 1.40835758 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.2727272728' to each side of the equation. -0.2727272728 + 0.2727272728 + x = 1.40835758 + 0.2727272728 Combine like terms: -0.2727272728 + 0.2727272728 = 0.0000000000 0.0000000000 + x = 1.40835758 + 0.2727272728 x = 1.40835758 + 0.2727272728 Combine like terms: 1.40835758 + 0.2727272728 = 1.6810848528 x = 1.6810848528 Simplifying x = 1.6810848528

Subproblem 2

x + -0.2727272728 = -1.40835758 Simplifying x + -0.2727272728 = -1.40835758 Reorder the terms: -0.2727272728 + x = -1.40835758 Solving -0.2727272728 + x = -1.40835758 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.2727272728' to each side of the equation. -0.2727272728 + 0.2727272728 + x = -1.40835758 + 0.2727272728 Combine like terms: -0.2727272728 + 0.2727272728 = 0.0000000000 0.0000000000 + x = -1.40835758 + 0.2727272728 x = -1.40835758 + 0.2727272728 Combine like terms: -1.40835758 + 0.2727272728 = -1.1356303072 x = -1.1356303072 Simplifying x = -1.1356303072

Solution

The solution to the problem is based on the solutions from the subproblems. x = {1.6810848528, -1.1356303072}

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