-3u(u+7)(u+3)=0

Solution for -3u(u+7)(u+3)=0 equation:

Simplifying
-3u(u + 7)(u + 3) = 0

Reorder the terms:
-3u(7 + u)(u + 3) = 0

Reorder the terms:
-3u(7 + u)(3 + u) = 0

Multiply (7 + u) * (3 + u)
-3u(7(3 + u) + u(3 + u)) = 0
-3u((3 * 7 + u * 7) + u(3 + u)) = 0
-3u((21 + 7u) + u(3 + u)) = 0
-3u(21 + 7u + (3 * u + u * u)) = 0
-3u(21 + 7u + (3u + u2)) = 0

Combine like terms: 7u + 3u = 10u
-3u(21 + 10u + u2) = 0
(21 * -3u + 10u * -3u + u2 * -3u) = 0
(-63u + -30u2 + -3u3) = 0

Solving
-63u + -30u2 + -3u3 = 0

Solving for variable 'u'.

Factor out the Greatest Common Factor (GCF), '-3u'.
-3u(21 + 10u + u2) = 0

Factor a trinomial.
-3u((7 + u)(3 + u)) = 0

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

Simplifying
u = 0

Solving
u = 0

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

Simplifying
u = 0
Subproblem 2
Set the factor '(7 + u)' equal to zero and attempt to solve:

Simplifying
7 + u = 0

Solving
7 + u = 0

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

Add '-7' to each side of the equation.
7 + -7 + u = 0 + -7

Combine like terms: 7 + -7 = 0
0 + u = 0 + -7
u = 0 + -7

Combine like terms: 0 + -7 = -7
u = -7

Simplifying
u = -7
Subproblem 3
Set the factor '(3 + u)' equal to zero and attempt to solve:

Simplifying
3 + u = 0

Solving
3 + u = 0

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

Add '-3' to each side of the equation.
3 + -3 + u = 0 + -3

Combine like terms: 3 + -3 = 0
0 + u = 0 + -3
u = 0 + -3

Combine like terms: 0 + -3 = -3
u = -3

Simplifying
u = -3
Solution
u = {0, -7, -3}