(a-3)(a+3)=0

Solution for (a-3)(a+3)=0 equation:

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

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

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

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

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

Solving
-9 + a2 = 0

Solving for variable 'a'.

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

Add '9' to each side of the equation.
-9 + 9 + a2 = 0 + 9

Combine like terms: -9 + 9 = 0
0 + a2 = 0 + 9
a2 = 0 + 9

Combine like terms: 0 + 9 = 9
a2 = 9

Simplifying
a2 = 9

Take the square root of each side:
a = {-3, 3}