Ответ:

  1. \(\sqrt[3]{\frac{125}{216}}=\frac{\sqrt[3]{125}}{\sqrt[3]{216}}=\frac56\).
  2. \(\frac{\sqrt[3]{54}}{\sqrt[3]{2}}=\sqrt[3]{27}=3\).
  3. \(\frac{\sqrt[3]{250}-\sqrt[3]{128}}{\sqrt[3]{2}}=\frac{5\sqrt[3]{2}-4\sqrt[3]{2}}{\sqrt[3]{2}}=1\).
  4. \(\frac{\sqrt[5]{x^3}}{\sqrt[5]{x^2}}=\sqrt[5]{x}\).

Ответ: 1) \(\frac56\); 2) 3; 3) 1; 4) \(\sqrt[5]{x}\).