1. Вычислите: 1) \(11^{-2}\); 2) \((-4)^{-3}\); 3) \(\left(-\frac{2}{5}\right)^{-2}\); 4) \(1,2^{-2}\).

1. Используем правило \(a^{-n}=\frac{1}{a^n}\): \(11^{-2}=\frac{1}{11^2}=\frac{1}{121}\).
2. \((-4)^{-3}=\frac{1}{(-4)^3}=-\frac{1}{64}\).
3. \(\left(-\frac{2}{5}\right)^{-2}=\left(-\frac{5}{2}\right)^2=\frac{25}{4}\).
4. \(1,2^{-2}=\frac{1}{1,2^2}=\frac{1}{1,44}=\frac{25}{36}\).

Ответ: 1) \(\frac{1}{121}\); 2) \(-\frac{1}{64}\); 3) \(\frac{25}{4}\); 4) \(\frac{25}{36}\).