(-2u^2-8u-4)-(9u^2+5u-7)+(-9u^2-6u-7)=

Solution for (-2u^2-8u-4)-(9u^2+5u-7)+(-9u^2-6u-7)= equation:

Simplifying
(-2u2 + -8u + -4) + -1(9u2 + 5u + -7) + (-9u2 + -6u + -7) = 0

Reorder the terms:
(-4 + -8u + -2u2) + -1(9u2 + 5u + -7) + (-9u2 + -6u + -7) = 0

Remove parenthesis around (-4 + -8u + -2u2)
-4 + -8u + -2u2 + -1(9u2 + 5u + -7) + (-9u2 + -6u + -7) = 0

Reorder the terms:
-4 + -8u + -2u2 + -1(-7 + 5u + 9u2) + (-9u2 + -6u + -7) = 0
-4 + -8u + -2u2 + (-7 * -1 + 5u * -1 + 9u2 * -1) + (-9u2 + -6u + -7) = 0
-4 + -8u + -2u2 + (7 + -5u + -9u2) + (-9u2 + -6u + -7) = 0

Reorder the terms:
-4 + -8u + -2u2 + 7 + -5u + -9u2 + (-7 + -6u + -9u2) = 0

Remove parenthesis around (-7 + -6u + -9u2)
-4 + -8u + -2u2 + 7 + -5u + -9u2 + -7 + -6u + -9u2 = 0

Reorder the terms:
-4 + 7 + -7 + -8u + -5u + -6u + -2u2 + -9u2 + -9u2 = 0

Combine like terms: -4 + 7 = 3
3 + -7 + -8u + -5u + -6u + -2u2 + -9u2 + -9u2 = 0

Combine like terms: 3 + -7 = -4
-4 + -8u + -5u + -6u + -2u2 + -9u2 + -9u2 = 0

Combine like terms: -8u + -5u = -13u
-4 + -13u + -6u + -2u2 + -9u2 + -9u2 = 0

Combine like terms: -13u + -6u = -19u
-4 + -19u + -2u2 + -9u2 + -9u2 = 0

Combine like terms: -2u2 + -9u2 = -11u2
-4 + -19u + -11u2 + -9u2 = 0

Combine like terms: -11u2 + -9u2 = -20u2
-4 + -19u + -20u2 = 0

Solving
-4 + -19u + -20u2 = 0

Solving for variable 'u'.

Factor out the Greatest Common Factor (GCF), '-1'.
-1(4 + 19u + 20u2) = 0

Ignore the factor -1.
Subproblem 1
Set the factor '(4 + 19u + 20u2)' equal to zero and attempt to solve:

Simplifying
4 + 19u + 20u2 = 0

Solving
4 + 19u + 20u2 = 0

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

Divide each side by '20'.
0.2 + 0.95u + u2 = 0.0

Move the constant term to the right:

Add '-0.2' to each side of the equation.
0.2 + 0.95u + -0.2 + u2 = 0.0 + -0.2

Reorder the terms:
0.2 + -0.2 + 0.95u + u2 = 0.0 + -0.2

Combine like terms: 0.2 + -0.2 = 0.0
0.0 + 0.95u + u2 = 0.0 + -0.2
0.95u + u2 = 0.0 + -0.2

Combine like terms: 0.0 + -0.2 = -0.2
0.95u + u2 = -0.2

The u term is 0.95u.  Take half its coefficient (0.475).
Square it (0.225625) and add it to both sides.

Add '0.225625' to each side of the equation.
0.95u + 0.225625 + u2 = -0.2 + 0.225625

Reorder the terms:
0.225625 + 0.95u + u2 = -0.2 + 0.225625

Combine like terms: -0.2 + 0.225625 = 0.025625
0.225625 + 0.95u + u2 = 0.025625

Factor a perfect square on the left side:
(u + 0.475)(u + 0.475) = 0.025625

Calculate the square root of the right side: 0.160078106

Break this problem into two subproblems by setting 
(u + 0.475) equal to 0.160078106 and -0.160078106.

Subproblem 1
u + 0.475 = 0.160078106

Simplifying
u + 0.475 = 0.160078106

Reorder the terms:
0.475 + u = 0.160078106

Solving
0.475 + u = 0.160078106

Solving for variable 'u'.

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

Add '-0.475' to each side of the equation.
0.475 + -0.475 + u = 0.160078106 + -0.475

Combine like terms: 0.475 + -0.475 = 0.000
0.000 + u = 0.160078106 + -0.475
u = 0.160078106 + -0.475

Combine like terms: 0.160078106 + -0.475 = -0.314921894
u = -0.314921894

Simplifying
u = -0.314921894

Subproblem 2
u + 0.475 = -0.160078106

Simplifying
u + 0.475 = -0.160078106

Reorder the terms:
0.475 + u = -0.160078106

Solving
0.475 + u = -0.160078106

Solving for variable 'u'.

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

Add '-0.475' to each side of the equation.
0.475 + -0.475 + u = -0.160078106 + -0.475

Combine like terms: 0.475 + -0.475 = 0.000
0.000 + u = -0.160078106 + -0.475
u = -0.160078106 + -0.475

Combine like terms: -0.160078106 + -0.475 = -0.635078106
u = -0.635078106

Simplifying
u = -0.635078106

Solution
The solution to the problem is based on the solutions
from the subproblems.
u = {-0.314921894, -0.635078106}
Solution
u = {-0.314921894, -0.635078106}