Ответ:

  1. \(\sqrt8\cdot\sqrt2=\sqrt{16}=4\).
  2. \(\frac{\sqrt{75}}{\sqrt3}=\sqrt{\frac{75}{3}}=\sqrt{25}=5\).
  3. \(\sqrt[3]{4}\cdot\sqrt[3]{16}=\sqrt[3]{64}=4\).
  4. \(\frac{\sqrt[4]{48}}{\sqrt[4]{3}}=\sqrt[4]{16}=2\).
  5. \(\sqrt{\sqrt[3]{729}}=\sqrt9=3\), поскольку \(\sqrt[3]{729}=9\).
  6. \(\sqrt{18}+\sqrt8=3\sqrt2+2\sqrt2=5\sqrt2\).