The given expression is:

$\frac{x^2 - 6x + 9}{x^2 - 9} - 7$

We need to simplify this expression to find which of the provided options is equivalent. Let's break it down step by step.

1. Factor the numerator and denominator of the fraction:
   • The numerator $x^2 - 6x + 9$ can be factored as $(x - 3)^2$.
   • The denominator $x^2 - 9$ is a difference of squares and factors as $(x - 3)(x + 3)$.

Thus, the expression becomes:

$\frac{(x - 3)^2}{(x - 3)(x + 3)} - 7$

2. Simplify the fraction: Cancel out one factor of $(x - 3)$ in both the numerator and denominator:

$\frac{x - 3}{x + 3} - 7$

3. Get a common denominator to combine terms:

[ \frac{x - 3}{x