Ответ:

  1. \(2\cdot2^{1/2}\cdot2^{1/4}\cdot2^{1/8}=2^{1+1/2+1/4+1/8}=2^{15/8}\).
  2. \(\left(\frac{2^{2/3}}{4^{5/6}}\right)^3=\left(\frac{2^{2/3}}{2^{5/3}}\right)^3=(2^{-1})^3=\frac18\).
  3. \(\sqrt{\frac{3\sqrt[3]9}{\sqrt[4]{27}}}=\sqrt{3^{1+2/3-3/4}}=\sqrt{3^{11/12}}=3^{11/24}\).
  4. \(\frac{a^{2/3}a^{-5/4}}{a^{3/2}a^{-1/3}}=a^{2/3-5/4-3/2+1/3}=a^{-7/4}\).
  5. \(\left((a^2)^{1/3}\right)^{3/5}=a^{2/3\cdot3/5}=a^{2/5}\).
  6. \(\frac{3^{1/3}7^{1/3}}{9^{1/3}}=\left(\frac{21}{9}\right)^{1/3}=\sqrt[3]{\frac73}\).