The problem asks to factor the expression $9x^2 - 49$ using the difference of squares factorization.

1. Problem Description

The problem asks to factor the expression $9x^2 - 49$ using the difference of squares factorization.

2. Solution Steps

The expression $9x^2 - 49$ is a difference of two squares. We can rewrite it as $(3x)^2 - (7)^2$. The difference of squares factorization is given by:

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

In this case, $a = 3x$ and $b = 7$. Substituting these values into the formula, we get:

$(3x)^2 - (7)^2 = (3x - 7)(3x + 7)$

3. Final Answer

$(3x - 7)(3x + 7)$