-20=x^2-13x

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Solution for -20=x^2-13x equation:


Simplifying
-20 = x2 + -13x

Reorder the terms:
-20 = -13x + x2

Solving
-20 = -13x + x2

Solving for variable 'x'.

Reorder the terms:
-20 + 13x + -1x2 = -13x + 13x + x2 + -1x2

Combine like terms: -13x + 13x = 0
-20 + 13x + -1x2 = 0 + x2 + -1x2
-20 + 13x + -1x2 = x2 + -1x2

Combine like terms: x2 + -1x2 = 0
-20 + 13x + -1x2 = 0

Begin completing the square.  Divide all terms by
-1 the coefficient of the squared term: 

Divide each side by '-1'.
20 + -13x + x2 = 0

Move the constant term to the right:

Add '-20' to each side of the equation.
20 + -13x + -20 + x2 = 0 + -20

Reorder the terms:
20 + -20 + -13x + x2 = 0 + -20

Combine like terms: 20 + -20 = 0
0 + -13x + x2 = 0 + -20
-13x + x2 = 0 + -20

Combine like terms: 0 + -20 = -20
-13x + x2 = -20

The x term is -13x.  Take half its coefficient (-6.5).
Square it (42.25) and add it to both sides.

Add '42.25' to each side of the equation.
-13x + 42.25 + x2 = -20 + 42.25

Reorder the terms:
42.25 + -13x + x2 = -20 + 42.25

Combine like terms: -20 + 42.25 = 22.25
42.25 + -13x + x2 = 22.25

Factor a perfect square on the left side:
(x + -6.5)(x + -6.5) = 22.25

Calculate the square root of the right side: 4.716990566

Break this problem into two subproblems by setting 
(x + -6.5) equal to 4.716990566 and -4.716990566.

Subproblem 1

x + -6.5 = 4.716990566 Simplifying x + -6.5 = 4.716990566 Reorder the terms: -6.5 + x = 4.716990566 Solving -6.5 + x = 4.716990566 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '6.5' to each side of the equation. -6.5 + 6.5 + x = 4.716990566 + 6.5 Combine like terms: -6.5 + 6.5 = 0.0 0.0 + x = 4.716990566 + 6.5 x = 4.716990566 + 6.5 Combine like terms: 4.716990566 + 6.5 = 11.216990566 x = 11.216990566 Simplifying x = 11.216990566

Subproblem 2

x + -6.5 = -4.716990566 Simplifying x + -6.5 = -4.716990566 Reorder the terms: -6.5 + x = -4.716990566 Solving -6.5 + x = -4.716990566 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '6.5' to each side of the equation. -6.5 + 6.5 + x = -4.716990566 + 6.5 Combine like terms: -6.5 + 6.5 = 0.0 0.0 + x = -4.716990566 + 6.5 x = -4.716990566 + 6.5 Combine like terms: -4.716990566 + 6.5 = 1.783009434 x = 1.783009434 Simplifying x = 1.783009434

Solution

The solution to the problem is based on the solutions from the subproblems. x = {11.216990566, 1.783009434}

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