x^2-18x+15=0

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Solution for x^2-18x+15=0 equation:


Simplifying
x2 + -18x + 15 = 0

Reorder the terms:
15 + -18x + x2 = 0

Solving
15 + -18x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '-15' to each side of the equation.
15 + -18x + -15 + x2 = 0 + -15

Reorder the terms:
15 + -15 + -18x + x2 = 0 + -15

Combine like terms: 15 + -15 = 0
0 + -18x + x2 = 0 + -15
-18x + x2 = 0 + -15

Combine like terms: 0 + -15 = -15
-18x + x2 = -15

The x term is -18x.  Take half its coefficient (-9).
Square it (81) and add it to both sides.

Add '81' to each side of the equation.
-18x + 81 + x2 = -15 + 81

Reorder the terms:
81 + -18x + x2 = -15 + 81

Combine like terms: -15 + 81 = 66
81 + -18x + x2 = 66

Factor a perfect square on the left side:
(x + -9)(x + -9) = 66

Calculate the square root of the right side: 8.124038405

Break this problem into two subproblems by setting 
(x + -9) equal to 8.124038405 and -8.124038405.

Subproblem 1

x + -9 = 8.124038405 Simplifying x + -9 = 8.124038405 Reorder the terms: -9 + x = 8.124038405 Solving -9 + x = 8.124038405 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '9' to each side of the equation. -9 + 9 + x = 8.124038405 + 9 Combine like terms: -9 + 9 = 0 0 + x = 8.124038405 + 9 x = 8.124038405 + 9 Combine like terms: 8.124038405 + 9 = 17.124038405 x = 17.124038405 Simplifying x = 17.124038405

Subproblem 2

x + -9 = -8.124038405 Simplifying x + -9 = -8.124038405 Reorder the terms: -9 + x = -8.124038405 Solving -9 + x = -8.124038405 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '9' to each side of the equation. -9 + 9 + x = -8.124038405 + 9 Combine like terms: -9 + 9 = 0 0 + x = -8.124038405 + 9 x = -8.124038405 + 9 Combine like terms: -8.124038405 + 9 = 0.875961595 x = 0.875961595 Simplifying x = 0.875961595

Solution

The solution to the problem is based on the solutions from the subproblems. x = {17.124038405, 0.875961595}

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