(x^2+3x)-3(x^2+3x)+2=0

Solution for (x^2+3x)-3(x^2+3x)+2=0 equation:

Simplifying
(x2 + 3x) + -3(x2 + 3x) + 2 = 0

Reorder the terms:
(3x + x2) + -3(x2 + 3x) + 2 = 0

Remove parenthesis around (3x + x2)
3x + x2 + -3(x2 + 3x) + 2 = 0

Reorder the terms:
3x + x2 + -3(3x + x2) + 2 = 0
3x + x2 + (3x * -3 + x2 * -3) + 2 = 0
3x + x2 + (-9x + -3x2) + 2 = 0

Reorder the terms:
2 + 3x + -9x + x2 + -3x2 = 0

Combine like terms: 3x + -9x = -6x
2 + -6x + x2 + -3x2 = 0

Combine like terms: x2 + -3x2 = -2x2
2 + -6x + -2x2 = 0

Solving
2 + -6x + -2x2 = 0

Solving for variable 'x'.

Factor out the Greatest Common Factor (GCF), '2'.
2(1 + -3x + -1x2) = 0

Ignore the factor 2.
Subproblem 1
Set the factor '(1 + -3x + -1x2)' equal to zero and attempt to solve:

Simplifying
1 + -3x + -1x2 = 0

Solving
1 + -3x + -1x2 = 0

Begin completing the square.  Divide all terms by
-1 the coefficient of the squared term: 

Divide each side by '-1'.
-1 + 3x + x2 = 0

Move the constant term to the right:

Add '1' to each side of the equation.
-1 + 3x + 1 + x2 = 0 + 1

Reorder the terms:
-1 + 1 + 3x + x2 = 0 + 1

Combine like terms: -1 + 1 = 0
0 + 3x + x2 = 0 + 1
3x + x2 = 0 + 1

Combine like terms: 0 + 1 = 1
3x + x2 = 1

The x term is 3x.  Take half its coefficient (1.5).
Square it (2.25) and add it to both sides.

Add '2.25' to each side of the equation.
3x + 2.25 + x2 = 1 + 2.25

Reorder the terms:
2.25 + 3x + x2 = 1 + 2.25

Combine like terms: 1 + 2.25 = 3.25
2.25 + 3x + x2 = 3.25

Factor a perfect square on the left side:
(x + 1.5)(x + 1.5) = 3.25

Calculate the square root of the right side: 1.802775638

Break this problem into two subproblems by setting 
(x + 1.5) equal to 1.802775638 and -1.802775638.

Subproblem 1
x + 1.5 = 1.802775638

Simplifying
x + 1.5 = 1.802775638

Reorder the terms:
1.5 + x = 1.802775638

Solving
1.5 + x = 1.802775638

Solving for variable 'x'.

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

Add '-1.5' to each side of the equation.
1.5 + -1.5 + x = 1.802775638 + -1.5

Combine like terms: 1.5 + -1.5 = 0.0
0.0 + x = 1.802775638 + -1.5
x = 1.802775638 + -1.5

Combine like terms: 1.802775638 + -1.5 = 0.302775638
x = 0.302775638

Simplifying
x = 0.302775638

Subproblem 2
x + 1.5 = -1.802775638

Simplifying
x + 1.5 = -1.802775638

Reorder the terms:
1.5 + x = -1.802775638

Solving
1.5 + x = -1.802775638

Solving for variable 'x'.

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

Add '-1.5' to each side of the equation.
1.5 + -1.5 + x = -1.802775638 + -1.5

Combine like terms: 1.5 + -1.5 = 0.0
0.0 + x = -1.802775638 + -1.5
x = -1.802775638 + -1.5

Combine like terms: -1.802775638 + -1.5 = -3.302775638
x = -3.302775638

Simplifying
x = -3.302775638

Solution
The solution to the problem is based on the solutions
from the subproblems.
x = {0.302775638, -3.302775638}
Solution
x = {0.302775638, -3.302775638}