To factor the binomial $x^2 - 16$ completely, we can use the difference of squares formula:

$a^2 - b^2 = (a + b)(a - b)$

Here:

• $a = x$
• $b = 4$, because $4^2 = 16$

So, we apply the formula as follows:

$x^2 - 16 = (x + 4)(x - 4)$

Final Answer:

$x^2 - 16 = (x + 4)(x - 4)$

Would you like a more detailed explanation of the steps?

Here are five related questions to practice:

1. How would you factor $x^2 - 25$?
2. How would you factor $x^2 - 49$?
3. Can you factor $x^2 + 16$ in real numbers?
4. How would you factor $x^2 - 9y^2$?
5. How would you factor $4x^2 - 36$?

Tip: The difference of squares formula only works for expressions with subtraction, not addition.