1. **State the problem:** Simplify the expression $$\frac{x^2 - 9}{x + 3}$$. 2. **Factor the numerator:** Notice that $$x^2 - 9$$ is a difference of squares, so we can write it as $$x^2 - 9 = (x - 3)(x + 3).$$ 3. **Rewrite the expression:** Substituting the factorized form, the expression becomes $$\frac{(x - 3)(x + 3)}{x + 3}.$$ 4. **Simplify by cancelling common factors:** Since $$x + 3$$ appears in both numerator and denominator, and $$x \neq -3$$ to avoid division by zero, we can cancel these terms: $$\frac{(x - 3)\cancel{(x + 3)}}{\cancel{x + 3}} = x - 3.$$ 5. **Final answer:** The simplified form is $$x - 3,$$ with the restriction $$x \neq -3$$.