x^2-15x+40=0

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Solution for x^2-15x+40=0 equation:


Simplifying
x2 + -15x + 40 = 0

Reorder the terms:
40 + -15x + x2 = 0

Solving
40 + -15x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '-40' to each side of the equation.
40 + -15x + -40 + x2 = 0 + -40

Reorder the terms:
40 + -40 + -15x + x2 = 0 + -40

Combine like terms: 40 + -40 = 0
0 + -15x + x2 = 0 + -40
-15x + x2 = 0 + -40

Combine like terms: 0 + -40 = -40
-15x + x2 = -40

The x term is -15x.  Take half its coefficient (-7.5).
Square it (56.25) and add it to both sides.

Add '56.25' to each side of the equation.
-15x + 56.25 + x2 = -40 + 56.25

Reorder the terms:
56.25 + -15x + x2 = -40 + 56.25

Combine like terms: -40 + 56.25 = 16.25
56.25 + -15x + x2 = 16.25

Factor a perfect square on the left side:
(x + -7.5)(x + -7.5) = 16.25

Calculate the square root of the right side: 4.031128874

Break this problem into two subproblems by setting 
(x + -7.5) equal to 4.031128874 and -4.031128874.

Subproblem 1

x + -7.5 = 4.031128874 Simplifying x + -7.5 = 4.031128874 Reorder the terms: -7.5 + x = 4.031128874 Solving -7.5 + x = 4.031128874 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '7.5' to each side of the equation. -7.5 + 7.5 + x = 4.031128874 + 7.5 Combine like terms: -7.5 + 7.5 = 0.0 0.0 + x = 4.031128874 + 7.5 x = 4.031128874 + 7.5 Combine like terms: 4.031128874 + 7.5 = 11.531128874 x = 11.531128874 Simplifying x = 11.531128874

Subproblem 2

x + -7.5 = -4.031128874 Simplifying x + -7.5 = -4.031128874 Reorder the terms: -7.5 + x = -4.031128874 Solving -7.5 + x = -4.031128874 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '7.5' to each side of the equation. -7.5 + 7.5 + x = -4.031128874 + 7.5 Combine like terms: -7.5 + 7.5 = 0.0 0.0 + x = -4.031128874 + 7.5 x = -4.031128874 + 7.5 Combine like terms: -4.031128874 + 7.5 = 3.468871126 x = 3.468871126 Simplifying x = 3.468871126

Solution

The solution to the problem is based on the solutions from the subproblems. x = {11.531128874, 3.468871126}

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