9x^2-36x+21=0

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Solution for 9x^2-36x+21=0 equation: 


Simplifying
9x2 + -36x + 21 = 0

Reorder the terms:
21 + -36x + 9x2 = 0

Solving
21 + -36x + 9x2 = 0

Solving for variable 'x'.

Factor out the Greatest Common Factor (GCF), '3'.
3(7 + -12x + 3x2) = 0

Ignore the factor 3.

Subproblem 1
Set the factor '(7 + -12x + 3x2)' equal to zero and attempt to solve:

Simplifying
7 + -12x + 3x2 = 0

Solving
7 + -12x + 3x2 = 0

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

Divide each side by '3'.
2.333333333 + -4x + x2 = 0

Move the constant term to the right:

Add '-2.333333333' to each side of the equation.
2.333333333 + -4x + -2.333333333 + x2 = 0 + -2.333333333

Reorder the terms:
2.333333333 + -2.333333333 + -4x + x2 = 0 + -2.333333333

Combine like terms: 2.333333333 + -2.333333333 = 0.000000000
0.000000000 + -4x + x2 = 0 + -2.333333333
-4x + x2 = 0 + -2.333333333

Combine like terms: 0 + -2.333333333 = -2.333333333
-4x + x2 = -2.333333333

The x term is -4x.  Take half its coefficient (-2).
Square it (4) and add it to both sides.

Add '4' to each side of the equation.
-4x + 4 + x2 = -2.333333333 + 4

Reorder the terms:
4 + -4x + x2 = -2.333333333 + 4

Combine like terms: -2.333333333 + 4 = 1.666666667
4 + -4x + x2 = 1.666666667

Factor a perfect square on the left side:
(x + -2)(x + -2) = 1.666666667

Calculate the square root of the right side: 1.290994449

Break this problem into two subproblems by setting 
(x + -2) equal to 1.290994449 and -1.290994449.


Subproblem 1
x + -2 = 1.290994449

Simplifying
x + -2 = 1.290994449

Reorder the terms:
-2 + x = 1.290994449

Solving
-2 + x = 1.290994449

Solving for variable 'x'.

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

Add '2' to each side of the equation.
-2 + 2 + x = 1.290994449 + 2

Combine like terms: -2 + 2 = 0
0 + x = 1.290994449 + 2
x = 1.290994449 + 2

Combine like terms: 1.290994449 + 2 = 3.290994449
x = 3.290994449

Simplifying
x = 3.290994449


Subproblem 2
x + -2 = -1.290994449

Simplifying
x + -2 = -1.290994449

Reorder the terms:
-2 + x = -1.290994449

Solving
-2 + x = -1.290994449

Solving for variable 'x'.

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

Add '2' to each side of the equation.
-2 + 2 + x = -1.290994449 + 2

Combine like terms: -2 + 2 = 0
0 + x = -1.290994449 + 2
x = -1.290994449 + 2

Combine like terms: -1.290994449 + 2 = 0.709005551
x = 0.709005551

Simplifying
x = 0.709005551


Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {3.290994449, 0.709005551}
Solution
x = {3.290994449, 0.709005551}

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