Ответ:

  1. \(2^{4/5}\cdot2^{11/5}=2^{15/5}=2^3=8\).
  2. \(5^{2/7}\cdot5^{5/7}=5^{7/7}=5\).
  3. \(9^{2/3}:9^{1/6}=9^{2/3-1/6}=9^{1/2}=3\).
  4. \(4^{1/3}:4^{5/6}=4^{1/3-5/6}=4^{-1/2}=\frac12\).
  5. \(\left(\frac1{8^{1/12}}\right)^{-4}=\left(8^{-1/12}\right)^{-4}=8^{1/3}=2\).

Ответ: 1) 8; 2) 5; 3) 3; 4) \(\frac12\); 5) 2.