1. The problem is to factor the expression $x^2 - 4$. 2. This is a difference of squares, which follows the formula $$a^2 - b^2 = (a - b)(a + b)$$. 3. Here, $a = x$ and $b = 2$ because $4 = 2^2$. 4. Substitute into the formula: $$x^2 - 4 = (x - 2)(x + 2)$$ 5. Therefore, the factored form of $x^2 - 4$ is $$ (x - 2)(x + 2) $$.