(-9x^3+3x^2-15x)+(-3x)=

Solution for (-9x^3+3x^2-15x)+(-3x)= equation:

Simplifying
(-9x3 + 3x2 + -15x) + (-3x) = 0

Reorder the terms:
(-15x + 3x2 + -9x3) + (-3x) = 0

Remove parenthesis around (-15x + 3x2 + -9x3)
-15x + 3x2 + -9x3 + (-3x) = 0

Reorder the terms:
-15x + (-3x) + 3x2 + -9x3 = 0

Combine like terms: -15x + (-3x) = -18x
-18x + 3x2 + -9x3 = 0

Solving
-18x + 3x2 + -9x3 = 0

Solving for variable 'x'.

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

Ignore the factor 3.
Subproblem 1
Set the factor 'x' equal to zero and attempt to solve:

Simplifying
x = 0

Solving
x = 0

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

Simplifying
x = 0
Subproblem 2
Set the factor '(-6 + x + -3x2)' equal to zero and attempt to solve:

Simplifying
-6 + x + -3x2 = 0

Solving
-6 + x + -3x2 = 0

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

Divide each side by '-3'.
2 + -0.3333333333x + x2 = 0

Move the constant term to the right:

Add '-2' to each side of the equation.
2 + -0.3333333333x + -2 + x2 = 0 + -2

Reorder the terms:
2 + -2 + -0.3333333333x + x2 = 0 + -2

Combine like terms: 2 + -2 = 0
0 + -0.3333333333x + x2 = 0 + -2
-0.3333333333x + x2 = 0 + -2

Combine like terms: 0 + -2 = -2
-0.3333333333x + x2 = -2

The x term is x.  Take half its coefficient (0.5).
Square it (0.25) and add it to both sides.

Add '0.25' to each side of the equation.
-0.3333333333x + 0.25 + x2 = -2 + 0.25

Reorder the terms:
0.25 + -0.3333333333x + x2 = -2 + 0.25

Combine like terms: -2 + 0.25 = -1.75
0.25 + -0.3333333333x + x2 = -1.75

Factor a perfect square on the left side:
(x + 0.5)(x + 0.5) = -1.75

Can't calculate square root of the right side.

The solution to this equation could not be determined.

This subproblem is being ignored because a solution could not be determined.
Solution
x = {0}