Ответ:

  1. \(\frac12<2^{2/3}<2^{3/4}<2<2^{4/3}\).
  2. \(\left(\frac13\right)^2<\left(\frac13\right)^{-1/2}<9^{1/3}<\left(\frac19\right)^{-3/2}<3^4\).
  3. \(\left(\frac9{25}\right)^2<\left(-\frac34\right)^{-4}<\left(\frac32\right)^4<2^4<(-3)^4\).
  4. \((-2)^3<\left(\frac23\right)^{-3}<3^3<2^6<\left(\frac1{27}\right)^{-2}\).