3) ((\frac{2}{7})^(\frac{27}{9}))((\frac{3}{5})^{-3})^\frac{5}{3};

3) $$(\frac{2}{7})^{(\frac{27}{9})}\cdot((\frac{3}{5})^{-3})^{\frac{5}{3}} = (\frac{2}{7})^3\cdot(\frac{3}{5})^{-3\cdot\frac{5}{3}} = (\frac{2}{7})^3\cdot(\frac{3}{5})^{-5} = \frac{2^3}{7^3}\cdot(\frac{5}{3})^5 = \frac{8}{343}\cdot\frac{3125}{243} = \frac{8 \cdot 3125}{343 \cdot 243} = \frac{25000}{83349}$$.

Ответ: $$\frac{25000}{83349}$$