18) $$\frac{32a^3}{9} \cdot \frac{18}{12a^2} =$$

$$\frac{32a^3}{9} \cdot \frac{18}{12a^2} = \frac{32a^3 \cdot 18}{9 \cdot 12a^2} = \frac{576a^3}{108a^2} = \frac{16a}{3}$$ Ответ: $$\frac{16a}{3}$$