x^2+20x+15=0

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Solution for x^2+20x+15=0 equation:


Simplifying
x2 + 20x + 15 = 0

Reorder the terms:
15 + 20x + x2 = 0

Solving
15 + 20x + 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 + 20x + -15 + x2 = 0 + -15

Reorder the terms:
15 + -15 + 20x + x2 = 0 + -15

Combine like terms: 15 + -15 = 0
0 + 20x + x2 = 0 + -15
20x + x2 = 0 + -15

Combine like terms: 0 + -15 = -15
20x + x2 = -15

The x term is 20x.  Take half its coefficient (10).
Square it (100) and add it to both sides.

Add '100' to each side of the equation.
20x + 100 + x2 = -15 + 100

Reorder the terms:
100 + 20x + x2 = -15 + 100

Combine like terms: -15 + 100 = 85
100 + 20x + x2 = 85

Factor a perfect square on the left side:
(x + 10)(x + 10) = 85

Calculate the square root of the right side: 9.219544457

Break this problem into two subproblems by setting 
(x + 10) equal to 9.219544457 and -9.219544457.

Subproblem 1

x + 10 = 9.219544457 Simplifying x + 10 = 9.219544457 Reorder the terms: 10 + x = 9.219544457 Solving 10 + x = 9.219544457 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-10' to each side of the equation. 10 + -10 + x = 9.219544457 + -10 Combine like terms: 10 + -10 = 0 0 + x = 9.219544457 + -10 x = 9.219544457 + -10 Combine like terms: 9.219544457 + -10 = -0.780455543 x = -0.780455543 Simplifying x = -0.780455543

Subproblem 2

x + 10 = -9.219544457 Simplifying x + 10 = -9.219544457 Reorder the terms: 10 + x = -9.219544457 Solving 10 + x = -9.219544457 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-10' to each side of the equation. 10 + -10 + x = -9.219544457 + -10 Combine like terms: 10 + -10 = 0 0 + x = -9.219544457 + -10 x = -9.219544457 + -10 Combine like terms: -9.219544457 + -10 = -19.219544457 x = -19.219544457 Simplifying x = -19.219544457

Solution

The solution to the problem is based on the solutions from the subproblems. x = {-0.780455543, -19.219544457}

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