20x+9x^2=28

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Solution for 20x+9x^2=28 equation:


Simplifying
20x + 9x2 = 28

Solving
20x + 9x2 = 28

Solving for variable 'x'.

Reorder the terms:
-28 + 20x + 9x2 = 28 + -28

Combine like terms: 28 + -28 = 0
-28 + 20x + 9x2 = 0

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

Divide each side by '9'.
-3.111111111 + 2.222222222x + x2 = 0

Move the constant term to the right:

Add '3.111111111' to each side of the equation.
-3.111111111 + 2.222222222x + 3.111111111 + x2 = 0 + 3.111111111

Reorder the terms:
-3.111111111 + 3.111111111 + 2.222222222x + x2 = 0 + 3.111111111

Combine like terms: -3.111111111 + 3.111111111 = 0.000000000
0.000000000 + 2.222222222x + x2 = 0 + 3.111111111
2.222222222x + x2 = 0 + 3.111111111

Combine like terms: 0 + 3.111111111 = 3.111111111
2.222222222x + x2 = 3.111111111

The x term is 2.222222222x.  Take half its coefficient (1.111111111).
Square it (1.234567901) and add it to both sides.

Add '1.234567901' to each side of the equation.
2.222222222x + 1.234567901 + x2 = 3.111111111 + 1.234567901

Reorder the terms:
1.234567901 + 2.222222222x + x2 = 3.111111111 + 1.234567901

Combine like terms: 3.111111111 + 1.234567901 = 4.345679012
1.234567901 + 2.222222222x + x2 = 4.345679012

Factor a perfect square on the left side:
(x + 1.111111111)(x + 1.111111111) = 4.345679012

Calculate the square root of the right side: 2.084629227

Break this problem into two subproblems by setting 
(x + 1.111111111) equal to 2.084629227 and -2.084629227.

Subproblem 1

x + 1.111111111 = 2.084629227 Simplifying x + 1.111111111 = 2.084629227 Reorder the terms: 1.111111111 + x = 2.084629227 Solving 1.111111111 + x = 2.084629227 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-1.111111111' to each side of the equation. 1.111111111 + -1.111111111 + x = 2.084629227 + -1.111111111 Combine like terms: 1.111111111 + -1.111111111 = 0.000000000 0.000000000 + x = 2.084629227 + -1.111111111 x = 2.084629227 + -1.111111111 Combine like terms: 2.084629227 + -1.111111111 = 0.973518116 x = 0.973518116 Simplifying x = 0.973518116

Subproblem 2

x + 1.111111111 = -2.084629227 Simplifying x + 1.111111111 = -2.084629227 Reorder the terms: 1.111111111 + x = -2.084629227 Solving 1.111111111 + x = -2.084629227 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-1.111111111' to each side of the equation. 1.111111111 + -1.111111111 + x = -2.084629227 + -1.111111111 Combine like terms: 1.111111111 + -1.111111111 = 0.000000000 0.000000000 + x = -2.084629227 + -1.111111111 x = -2.084629227 + -1.111111111 Combine like terms: -2.084629227 + -1.111111111 = -3.195740338 x = -3.195740338 Simplifying x = -3.195740338

Solution

The solution to the problem is based on the solutions from the subproblems. x = {0.973518116, -3.195740338}

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