15=-3x(x-1)+9

Solution for 15=-3x(x-1)+9 equation:

Simplifying
15 = -3x(x + -1) + 9

Reorder the terms:
15 = -3x(-1 + x) + 9
15 = (-1 * -3x + x * -3x) + 9
15 = (3x + -3x2) + 9

Reorder the terms:
15 = 9 + 3x + -3x2

Solving
15 = 9 + 3x + -3x2

Solving for variable 'x'.

Combine like terms: 15 + -9 = 6
6 + -3x + 3x2 = 9 + 3x + -3x2 + -9 + -3x + 3x2

Reorder the terms:
6 + -3x + 3x2 = 9 + -9 + 3x + -3x + -3x2 + 3x2

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

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

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

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

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

Simplifying
2 + -1x + x2 = 0

Solving
2 + -1x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-2' to each side of the equation.
2 + -1x + -2 + x2 = 0 + -2

Reorder the terms:
2 + -2 + -1x + x2 = 0 + -2

Combine like terms: 2 + -2 = 0
0 + -1x + x2 = 0 + -2
-1x + x2 = 0 + -2

Combine like terms: 0 + -2 = -2
-1x + x2 = -2

The x term is -1x.  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.
-1x + 0.25 + x2 = -2 + 0.25

Reorder the terms:
0.25 + -1x + x2 = -2 + 0.25

Combine like terms: -2 + 0.25 = -1.75
0.25 + -1x + 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.

The solution to this equation could not be determined.