2) a) (-16x²/27y³)² * (9y²/8x²)³;

2) a) $$\left(-\frac{16x^2}{27y^3}\right)^2 \cdot \left(\frac{9y^2}{8x^2}\right)^3 = \frac{256x^4}{729y^6} \cdot \frac{729y^6}{512x^6} = \frac{1}{2} \cdot \frac{1}{x^2} = \frac{1}{2x^2}$$

Ответ: 1/(2x²)