x^2+20x+42=0

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Solution for x^2+20x+42=0 equation:


Simplifying
x2 + 20x + 42 = 0

Reorder the terms:
42 + 20x + x2 = 0

Solving
42 + 20x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '-42' to each side of the equation.
42 + 20x + -42 + x2 = 0 + -42

Reorder the terms:
42 + -42 + 20x + x2 = 0 + -42

Combine like terms: 42 + -42 = 0
0 + 20x + x2 = 0 + -42
20x + x2 = 0 + -42

Combine like terms: 0 + -42 = -42
20x + x2 = -42

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 = -42 + 100

Reorder the terms:
100 + 20x + x2 = -42 + 100

Combine like terms: -42 + 100 = 58
100 + 20x + x2 = 58

Factor a perfect square on the left side:
(x + 10)(x + 10) = 58

Calculate the square root of the right side: 7.615773106

Break this problem into two subproblems by setting 
(x + 10) equal to 7.615773106 and -7.615773106.

Subproblem 1

x + 10 = 7.615773106 Simplifying x + 10 = 7.615773106 Reorder the terms: 10 + x = 7.615773106 Solving 10 + x = 7.615773106 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 = 7.615773106 + -10 Combine like terms: 10 + -10 = 0 0 + x = 7.615773106 + -10 x = 7.615773106 + -10 Combine like terms: 7.615773106 + -10 = -2.384226894 x = -2.384226894 Simplifying x = -2.384226894

Subproblem 2

x + 10 = -7.615773106 Simplifying x + 10 = -7.615773106 Reorder the terms: 10 + x = -7.615773106 Solving 10 + x = -7.615773106 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 = -7.615773106 + -10 Combine like terms: 10 + -10 = 0 0 + x = -7.615773106 + -10 x = -7.615773106 + -10 Combine like terms: -7.615773106 + -10 = -17.615773106 x = -17.615773106 Simplifying x = -17.615773106

Solution

The solution to the problem is based on the solutions from the subproblems. x = {-2.384226894, -17.615773106}

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