1. **State the problem:** Find the horizontal asymptote of the function $$y = \frac{9x - 36}{3x + 3}$$. 2. **Recall the rule for horizontal asymptotes:** For a rational function $$\frac{ax + b}{cx + d}$$, if the degrees of numerator and denominator are equal (both degree 1 here), the horizontal asymptote is $$y = \frac{a}{c}$$, the ratio of the leading coefficients. 3. **Identify leading coefficients:** Numerator leading coefficient is 9, denominator leading coefficient is 3. 4. **Calculate the horizontal asymptote:** $$y = \frac{9}{3} = 3$$ 5. **Interpretation:** As $$x \to \pm \infty$$, the function approaches the line $$y = 3$$. **Final answer:** $$y = 3$$