Let there be a rational number \(\frac{a}{b}\) then \((\frac{a}{b})^{-1}\) = \(\frac{b}{a}\)
Therefore,
(i)
\((\frac{5}{8})^{-1}=\frac{8}{5}\)
(ii)
\((\frac{-4}{9})^{-1}=\frac{9}{-4} =\frac{9\times-1}{-4\times-1}=\frac{-9}{4}\)
(iii)
\((-7)^{-1}=(\frac{-7}{1})^{-1}=\frac{1}{-7}= \frac{1\times-1}{-7\times-1}=\frac{-1}{7}\)
(iv)
\((\frac{1}{-3})^{-1}=\frac{-3}{1}=-3\)