3) а)
\[ (3^{-1})^{-2} = 3^{(-1) \times (-2)} = 3^2 = 9 \]
3) б)
\[ (0.1^{-2})^{-3} = 0.1^{(-2) \times (-3)} = 0.1^6 = \left(\frac{1}{10}\right)^6 = \frac{1}{10^6} = \frac{1}{1000000} \]