x^2-8x-45=0

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Solution for x^2-8x-45=0 equation:


Simplifying
x2 + -8x + -45 = 0

Reorder the terms:
-45 + -8x + x2 = 0

Solving
-45 + -8x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '45' to each side of the equation.
-45 + -8x + 45 + x2 = 0 + 45

Reorder the terms:
-45 + 45 + -8x + x2 = 0 + 45

Combine like terms: -45 + 45 = 0
0 + -8x + x2 = 0 + 45
-8x + x2 = 0 + 45

Combine like terms: 0 + 45 = 45
-8x + x2 = 45

The x term is -8x.  Take half its coefficient (-4).
Square it (16) and add it to both sides.

Add '16' to each side of the equation.
-8x + 16 + x2 = 45 + 16

Reorder the terms:
16 + -8x + x2 = 45 + 16

Combine like terms: 45 + 16 = 61
16 + -8x + x2 = 61

Factor a perfect square on the left side:
(x + -4)(x + -4) = 61

Calculate the square root of the right side: 7.810249676

Break this problem into two subproblems by setting 
(x + -4) equal to 7.810249676 and -7.810249676.

Subproblem 1

x + -4 = 7.810249676 Simplifying x + -4 = 7.810249676 Reorder the terms: -4 + x = 7.810249676 Solving -4 + x = 7.810249676 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '4' to each side of the equation. -4 + 4 + x = 7.810249676 + 4 Combine like terms: -4 + 4 = 0 0 + x = 7.810249676 + 4 x = 7.810249676 + 4 Combine like terms: 7.810249676 + 4 = 11.810249676 x = 11.810249676 Simplifying x = 11.810249676

Subproblem 2

x + -4 = -7.810249676 Simplifying x + -4 = -7.810249676 Reorder the terms: -4 + x = -7.810249676 Solving -4 + x = -7.810249676 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '4' to each side of the equation. -4 + 4 + x = -7.810249676 + 4 Combine like terms: -4 + 4 = 0 0 + x = -7.810249676 + 4 x = -7.810249676 + 4 Combine like terms: -7.810249676 + 4 = -3.810249676 x = -3.810249676 Simplifying x = -3.810249676

Solution

The solution to the problem is based on the solutions from the subproblems. x = {11.810249676, -3.810249676}

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