Question: What is the factored form of the quadratic expression x^2 - 9?

Options:

1. (x - 3)(x + 3)
2. (x - 9)(x + 1)
3. (x - 1)(x + 1)
4. (x + 3)(x + 3)

Correct Answer: (x - 3)(x + 3)

Solution:

The expression x^2 - 9 is a difference of squares, which factors to (x - 3)(x + 3).