1. The problem is to factor the expression $x^2 - 16$. 2. Recognize that this is a difference of squares, which follows the formula $a^2 - b^2 = (a - b)(a + b)$. 3. Here, $a = x$ and $b = 4$ because $16 = 4^2$. 4. Applying the formula, we get: $$x^2 - 16 = (x - 4)(x + 4)$$ 5. This means the expression factors into two binomials, one subtracting 4 and the other adding 4 to $x$. 6. This factorization is useful for solving equations or simplifying expressions involving $x^2 - 16$.