9a(a+1)=0

Solution for 9a(a+1)=0 equation:

Simplifying
9a(a + 1) = 0

Reorder the terms:
9a(1 + a) = 0
(1 * 9a + a * 9a) = 0
(9a + 9a2) = 0

Solving
9a + 9a2 = 0

Solving for variable 'a'.

Factor out the Greatest Common Factor (GCF), '9a'.
9a(1 + 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 '(1 + a)' equal to zero and attempt to solve:

Simplifying
1 + a = 0

Solving
1 + a = 0

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

Add '-1' to each side of the equation.
1 + -1 + a = 0 + -1

Combine like terms: 1 + -1 = 0
0 + a = 0 + -1
a = 0 + -1

Combine like terms: 0 + -1 = -1
a = -1

Simplifying
a = -1
Solution
a = {0, -1}