-9a(a+4)=0

Solution for -9a(a+4)=0 equation:

Simplifying
-9a(a + 4) = 0

Reorder the terms:
-9a(4 + a) = 0
(4 * -9a + a * -9a) = 0
(-36a + -9a2) = 0

Solving
-36a + -9a2 = 0

Solving for variable 'a'.

Factor out the Greatest Common Factor (GCF), '-9a'.
-9a(4 + a) = 0

Ignore the factor -9.
Subproblem 1
Set the factor 'a' equal to zero and attempt to solve:

Simplifying
a = 0

Solving
a = 0

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

Simplifying
a = 0
Subproblem 2
Set the factor '(4 + a)' equal to zero and attempt to solve:

Simplifying
4 + a = 0

Solving
4 + a = 0

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

Add '-4' to each side of the equation.
4 + -4 + a = 0 + -4

Combine like terms: 4 + -4 = 0
0 + a = 0 + -4
a = 0 + -4

Combine like terms: 0 + -4 = -4
a = -4

Simplifying
a = -4
Solution
a = {0, -4}