18x^2-7x-9=0

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Solution for 18x^2-7x-9=0 equation:


Simplifying
18x2 + -7x + -9 = 0

Reorder the terms:
-9 + -7x + 18x2 = 0

Solving
-9 + -7x + 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 + -0.3888888889x + x2 = 0

Move the constant term to the right:

Add '0.5' to each side of the equation.
-0.5 + -0.3888888889x + 0.5 + x2 = 0 + 0.5

Reorder the terms:
-0.5 + 0.5 + -0.3888888889x + x2 = 0 + 0.5

Combine like terms: -0.5 + 0.5 = 0.0
0.0 + -0.3888888889x + x2 = 0 + 0.5
-0.3888888889x + x2 = 0 + 0.5

Combine like terms: 0 + 0.5 = 0.5
-0.3888888889x + x2 = 0.5

The x term is -0.3888888889x.  Take half its coefficient (-0.1944444445).
Square it (0.03780864200) and add it to both sides.

Add '0.03780864200' to each side of the equation.
-0.3888888889x + 0.03780864200 + x2 = 0.5 + 0.03780864200

Reorder the terms:
0.03780864200 + -0.3888888889x + x2 = 0.5 + 0.03780864200

Combine like terms: 0.5 + 0.03780864200 = 0.537808642
0.03780864200 + -0.3888888889x + x2 = 0.537808642

Factor a perfect square on the left side:
(x + -0.1944444445)(x + -0.1944444445) = 0.537808642

Calculate the square root of the right side: 0.733354377

Break this problem into two subproblems by setting 
(x + -0.1944444445) equal to 0.733354377 and -0.733354377.

Subproblem 1

x + -0.1944444445 = 0.733354377 Simplifying x + -0.1944444445 = 0.733354377 Reorder the terms: -0.1944444445 + x = 0.733354377 Solving -0.1944444445 + x = 0.733354377 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.1944444445' to each side of the equation. -0.1944444445 + 0.1944444445 + x = 0.733354377 + 0.1944444445 Combine like terms: -0.1944444445 + 0.1944444445 = 0.0000000000 0.0000000000 + x = 0.733354377 + 0.1944444445 x = 0.733354377 + 0.1944444445 Combine like terms: 0.733354377 + 0.1944444445 = 0.9277988215 x = 0.9277988215 Simplifying x = 0.9277988215

Subproblem 2

x + -0.1944444445 = -0.733354377 Simplifying x + -0.1944444445 = -0.733354377 Reorder the terms: -0.1944444445 + x = -0.733354377 Solving -0.1944444445 + x = -0.733354377 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.1944444445' to each side of the equation. -0.1944444445 + 0.1944444445 + x = -0.733354377 + 0.1944444445 Combine like terms: -0.1944444445 + 0.1944444445 = 0.0000000000 0.0000000000 + x = -0.733354377 + 0.1944444445 x = -0.733354377 + 0.1944444445 Combine like terms: -0.733354377 + 0.1944444445 = -0.5389099325 x = -0.5389099325 Simplifying x = -0.5389099325

Solution

The solution to the problem is based on the solutions from the subproblems. x = {0.9277988215, -0.5389099325}

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