(a+3)(a+9)=

Solution for (a+3)(a+9)= equation:

Simplifying
(a + 3)(a + 9) = 0

Reorder the terms:
(3 + a)(a + 9) = 0

Reorder the terms:
(3 + a)(9 + a) = 0

Multiply (3 + a) * (9 + a)
(3(9 + a) + a(9 + a)) = 0
((9 * 3 + a * 3) + a(9 + a)) = 0
((27 + 3a) + a(9 + a)) = 0
(27 + 3a + (9 * a + a * a)) = 0
(27 + 3a + (9a + a2)) = 0

Combine like terms: 3a + 9a = 12a
(27 + 12a + a2) = 0

Solving
27 + 12a + a2 = 0

Solving for variable 'a'.

Factor a trinomial.
(9 + a)(3 + a) = 0

Subproblem 1
Set the factor '(9 + a)' equal to zero and attempt to solve:

Simplifying
9 + a = 0

Solving
9 + a = 0

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

Add '-9' to each side of the equation.
9 + -9 + a = 0 + -9

Combine like terms: 9 + -9 = 0
0 + a = 0 + -9
a = 0 + -9

Combine like terms: 0 + -9 = -9
a = -9

Simplifying
a = -9
Subproblem 2
Set the factor '(3 + a)' equal to zero and attempt to solve:

Simplifying
3 + a = 0

Solving
3 + a = 0

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

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

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

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

Simplifying
a = -3
Solution
a = {-9, -3}