\[\mathbf{\ }\frac{3x + 6}{x + 3} \cdot \frac{x^{2} - 9}{x^{2} - 4} =\]
\[= \frac{3 \cdot (x + 2)(x - 3)(x + 3)}{(x + 3)(x + 2)(x - 2)} = \frac{3x - 9}{x - 2}\]