18x^2-12x-9=0

Solution for 18x^2-12x-9=0 equation:

Simplifying
18x2 + -12x + -9 = 0

Reorder the terms:
-9 + -12x + 18x2 = 0

Solving
-9 + -12x + 18x2 = 0

Solving for variable 'x'.

Factor out the Greatest Common Factor (GCF), '3'.
3(-3 + -4x + 6x2) = 0

Ignore the factor 3.
Subproblem 1
Set the factor '(-3 + -4x + 6x2)' equal to zero and attempt to solve:

Simplifying
-3 + -4x + 6x2 = 0

Solving
-3 + -4x + 6x2 = 0

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

Divide each side by '6'.
-0.5 + -0.6666666667x + x2 = 0

Move the constant term to the right:

Add '0.5' to each side of the equation.
-0.5 + -0.6666666667x + 0.5 + x2 = 0 + 0.5

Reorder the terms:
-0.5 + 0.5 + -0.6666666667x + x2 = 0 + 0.5

Combine like terms: -0.5 + 0.5 = 0.0
0.0 + -0.6666666667x + x2 = 0 + 0.5
-0.6666666667x + x2 = 0 + 0.5

Combine like terms: 0 + 0.5 = 0.5
-0.6666666667x + x2 = 0.5

The x term is -0.6666666667x.  Take half its coefficient (-0.3333333334).
Square it (0.1111111112) and add it to both sides.

Add '0.1111111112' to each side of the equation.
-0.6666666667x + 0.1111111112 + x2 = 0.5 + 0.1111111112

Reorder the terms:
0.1111111112 + -0.6666666667x + x2 = 0.5 + 0.1111111112

Combine like terms: 0.5 + 0.1111111112 = 0.6111111112
0.1111111112 + -0.6666666667x + x2 = 0.6111111112

Factor a perfect square on the left side:
(x + -0.3333333334)(x + -0.3333333334) = 0.6111111112

Calculate the square root of the right side: 0.78173596

Break this problem into two subproblems by setting 
(x + -0.3333333334) equal to 0.78173596 and -0.78173596.

Subproblem 1
x + -0.3333333334 = 0.78173596

Simplifying
x + -0.3333333334 = 0.78173596

Reorder the terms:
-0.3333333334 + x = 0.78173596

Solving
-0.3333333334 + x = 0.78173596

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '0.3333333334' to each side of the equation.
-0.3333333334 + 0.3333333334 + x = 0.78173596 + 0.3333333334

Combine like terms: -0.3333333334 + 0.3333333334 = 0.0000000000
0.0000000000 + x = 0.78173596 + 0.3333333334
x = 0.78173596 + 0.3333333334

Combine like terms: 0.78173596 + 0.3333333334 = 1.1150692934
x = 1.1150692934

Simplifying
x = 1.1150692934

Subproblem 2
x + -0.3333333334 = -0.78173596

Simplifying
x + -0.3333333334 = -0.78173596

Reorder the terms:
-0.3333333334 + x = -0.78173596

Solving
-0.3333333334 + x = -0.78173596

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '0.3333333334' to each side of the equation.
-0.3333333334 + 0.3333333334 + x = -0.78173596 + 0.3333333334

Combine like terms: -0.3333333334 + 0.3333333334 = 0.0000000000
0.0000000000 + x = -0.78173596 + 0.3333333334
x = -0.78173596 + 0.3333333334

Combine like terms: -0.78173596 + 0.3333333334 = -0.4484026266
x = -0.4484026266

Simplifying
x = -0.4484026266

Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {1.1150692934, -0.4484026266}
Solution
x = {1.1150692934, -0.4484026266}