18x^2-20x-9=0

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Solution for 18x^2-20x-9=0 equation:


Simplifying
18x2 + -20x + -9 = 0

Reorder the terms:
-9 + -20x + 18x2 = 0

Solving
-9 + -20x + 18x2 = 0

Solving for variable 'x'.

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

Divide each side by '18'.
-0.5 + -1.111111111x + x2 = 0

Move the constant term to the right:

Add '0.5' to each side of the equation.
-0.5 + -1.111111111x + 0.5 + x2 = 0 + 0.5

Reorder the terms:
-0.5 + 0.5 + -1.111111111x + x2 = 0 + 0.5

Combine like terms: -0.5 + 0.5 = 0.0
0.0 + -1.111111111x + x2 = 0 + 0.5
-1.111111111x + x2 = 0 + 0.5

Combine like terms: 0 + 0.5 = 0.5
-1.111111111x + x2 = 0.5

The x term is -1.111111111x.  Take half its coefficient (-0.5555555555).
Square it (0.3086419752) and add it to both sides.

Add '0.3086419752' to each side of the equation.
-1.111111111x + 0.3086419752 + x2 = 0.5 + 0.3086419752

Reorder the terms:
0.3086419752 + -1.111111111x + x2 = 0.5 + 0.3086419752

Combine like terms: 0.5 + 0.3086419752 = 0.8086419752
0.3086419752 + -1.111111111x + x2 = 0.8086419752

Factor a perfect square on the left side:
(x + -0.5555555555)(x + -0.5555555555) = 0.8086419752

Calculate the square root of the right side: 0.899245225

Break this problem into two subproblems by setting 
(x + -0.5555555555) equal to 0.899245225 and -0.899245225.

Subproblem 1

x + -0.5555555555 = 0.899245225 Simplifying x + -0.5555555555 = 0.899245225 Reorder the terms: -0.5555555555 + x = 0.899245225 Solving -0.5555555555 + x = 0.899245225 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.5555555555' to each side of the equation. -0.5555555555 + 0.5555555555 + x = 0.899245225 + 0.5555555555 Combine like terms: -0.5555555555 + 0.5555555555 = 0.0000000000 0.0000000000 + x = 0.899245225 + 0.5555555555 x = 0.899245225 + 0.5555555555 Combine like terms: 0.899245225 + 0.5555555555 = 1.4548007805 x = 1.4548007805 Simplifying x = 1.4548007805

Subproblem 2

x + -0.5555555555 = -0.899245225 Simplifying x + -0.5555555555 = -0.899245225 Reorder the terms: -0.5555555555 + x = -0.899245225 Solving -0.5555555555 + x = -0.899245225 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.5555555555' to each side of the equation. -0.5555555555 + 0.5555555555 + x = -0.899245225 + 0.5555555555 Combine like terms: -0.5555555555 + 0.5555555555 = 0.0000000000 0.0000000000 + x = -0.899245225 + 0.5555555555 x = -0.899245225 + 0.5555555555 Combine like terms: -0.899245225 + 0.5555555555 = -0.3436896695 x = -0.3436896695 Simplifying x = -0.3436896695

Solution

The solution to the problem is based on the solutions from the subproblems. x = {1.4548007805, -0.3436896695}

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