1. Statement of the problem: The correct expression should be $x^2 - 4$. 2. Recognize the pattern: This is a difference of squares because $x^2 - 4 = x^2 - 2^2$. 3. Apply the factorization formula: For $a^2 - b^2$ we have $a^2 - b^2 = (a - b)(a + b)$, so with $a = x$ and $b = 2$ we get $x^2 - 4 = (x - 2)(x + 2)$. 4. Check by expanding: Multiply $(x - 2)(x + 2)$ to get $x^2 + 2x - 2x - 4 = x^2 - 4$, which matches the original expression. 5. Final answer: $x^2 - 4 = (x - 2)(x + 2)$.