Ответ:

  1. \(\sqrt{b^{-1}}=(b^{-1})^{\frac12}=b^{-\frac12}\).
  2. \(\sqrt[12]{b^{-5}}=(b^{-5})^{\frac1{12}}=b^{-\frac5{12}}\).
  3. \(\frac1{\sqrt[4]{x^{-3}}}=x^{\frac34}\).
  4. \(\frac1{\sqrt[3]{a^{-2}}}=a^{\frac23}\).

Ответ: а) \(b^{-\frac12}\); б) \(b^{-\frac5{12}}\); в) \(x^{\frac34}\); г) \(a^{\frac23}\).