(a+2)(a-2)=12

Solution for (a+2)(a-2)=12 equation:

Simplifying
(a + 2)(a + -2) = 12

Reorder the terms:
(2 + a)(a + -2) = 12

Reorder the terms:
(2 + a)(-2 + a) = 12

Multiply (2 + a) * (-2 + a)
(2(-2 + a) + a(-2 + a)) = 12
((-2 * 2 + a * 2) + a(-2 + a)) = 12
((-4 + 2a) + a(-2 + a)) = 12
(-4 + 2a + (-2 * a + a * a)) = 12
(-4 + 2a + (-2a + a2)) = 12

Combine like terms: 2a + -2a = 0
(-4 + 0 + a2) = 12
(-4 + a2) = 12

Solving
-4 + a2 = 12

Solving for variable 'a'.

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

Add '4' to each side of the equation.
-4 + 4 + a2 = 12 + 4

Combine like terms: -4 + 4 = 0
0 + a2 = 12 + 4
a2 = 12 + 4

Combine like terms: 12 + 4 = 16
a2 = 16

Simplifying
a2 = 16

Take the square root of each side:
a = {-4, 4}