10*x^2+20*x+9=0

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Solution for 10*x^2+20*x+9=0 equation:


Simplifying
10x2 + 20x + 9 = 0

Reorder the terms:
9 + 20x + 10x2 = 0

Solving
9 + 20x + 10x2 = 0

Solving for variable 'x'.

Begin completing the square.  Divide all terms by
10 the coefficient of the squared term: 

Divide each side by '10'.
0.9 + 2x + x2 = 0

Move the constant term to the right:

Add '-0.9' to each side of the equation.
0.9 + 2x + -0.9 + x2 = 0 + -0.9

Reorder the terms:
0.9 + -0.9 + 2x + x2 = 0 + -0.9

Combine like terms: 0.9 + -0.9 = 0.0
0.0 + 2x + x2 = 0 + -0.9
2x + x2 = 0 + -0.9

Combine like terms: 0 + -0.9 = -0.9
2x + x2 = -0.9

The x term is 2x.  Take half its coefficient (1).
Square it (1) and add it to both sides.

Add '1' to each side of the equation.
2x + 1 + x2 = -0.9 + 1

Reorder the terms:
1 + 2x + x2 = -0.9 + 1

Combine like terms: -0.9 + 1 = 0.1
1 + 2x + x2 = 0.1

Factor a perfect square on the left side:
(x + 1)(x + 1) = 0.1

Calculate the square root of the right side: 0.316227766

Break this problem into two subproblems by setting 
(x + 1) equal to 0.316227766 and -0.316227766.

Subproblem 1

x + 1 = 0.316227766 Simplifying x + 1 = 0.316227766 Reorder the terms: 1 + x = 0.316227766 Solving 1 + x = 0.316227766 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-1' to each side of the equation. 1 + -1 + x = 0.316227766 + -1 Combine like terms: 1 + -1 = 0 0 + x = 0.316227766 + -1 x = 0.316227766 + -1 Combine like terms: 0.316227766 + -1 = -0.683772234 x = -0.683772234 Simplifying x = -0.683772234

Subproblem 2

x + 1 = -0.316227766 Simplifying x + 1 = -0.316227766 Reorder the terms: 1 + x = -0.316227766 Solving 1 + x = -0.316227766 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-1' to each side of the equation. 1 + -1 + x = -0.316227766 + -1 Combine like terms: 1 + -1 = 0 0 + x = -0.316227766 + -1 x = -0.316227766 + -1 Combine like terms: -0.316227766 + -1 = -1.316227766 x = -1.316227766 Simplifying x = -1.316227766

Solution

The solution to the problem is based on the solutions from the subproblems. x = {-0.683772234, -1.316227766}

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