x^2-40x+72=0

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Solution for x^2-40x+72=0 equation:


Simplifying
x2 + -40x + 72 = 0

Reorder the terms:
72 + -40x + x2 = 0

Solving
72 + -40x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '-72' to each side of the equation.
72 + -40x + -72 + x2 = 0 + -72

Reorder the terms:
72 + -72 + -40x + x2 = 0 + -72

Combine like terms: 72 + -72 = 0
0 + -40x + x2 = 0 + -72
-40x + x2 = 0 + -72

Combine like terms: 0 + -72 = -72
-40x + x2 = -72

The x term is -40x.  Take half its coefficient (-20).
Square it (400) and add it to both sides.

Add '400' to each side of the equation.
-40x + 400 + x2 = -72 + 400

Reorder the terms:
400 + -40x + x2 = -72 + 400

Combine like terms: -72 + 400 = 328
400 + -40x + x2 = 328

Factor a perfect square on the left side:
(x + -20)(x + -20) = 328

Calculate the square root of the right side: 18.110770276

Break this problem into two subproblems by setting 
(x + -20) equal to 18.110770276 and -18.110770276.

Subproblem 1

x + -20 = 18.110770276 Simplifying x + -20 = 18.110770276 Reorder the terms: -20 + x = 18.110770276 Solving -20 + x = 18.110770276 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '20' to each side of the equation. -20 + 20 + x = 18.110770276 + 20 Combine like terms: -20 + 20 = 0 0 + x = 18.110770276 + 20 x = 18.110770276 + 20 Combine like terms: 18.110770276 + 20 = 38.110770276 x = 38.110770276 Simplifying x = 38.110770276

Subproblem 2

x + -20 = -18.110770276 Simplifying x + -20 = -18.110770276 Reorder the terms: -20 + x = -18.110770276 Solving -20 + x = -18.110770276 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '20' to each side of the equation. -20 + 20 + x = -18.110770276 + 20 Combine like terms: -20 + 20 = 0 0 + x = -18.110770276 + 20 x = -18.110770276 + 20 Combine like terms: -18.110770276 + 20 = 1.889229724 x = 1.889229724 Simplifying x = 1.889229724

Solution

The solution to the problem is based on the solutions from the subproblems. x = {38.110770276, 1.889229724}

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