a) $\dfrac{{{a^{\frac{4}{3}}}\left( {{a^{\frac{{ - 1}}{3}}} + {a^{\frac{2}{3}}}} \right)}}{{{a^{\frac{1}{4}}}\left( {{a^{\frac{3}{4}}} + {a^{\frac{{ - 1}}{4}}}} \right)}};$

b) $\dfrac{{{b^{\frac{1}{5}}}\left( {\sqrt[5]{{{b^4}}} - {\rm{ }}\sqrt[5]{{{b^{ - 1}}}}} \right)}}{{{b^{\frac{2}{3}}}\left( {\sqrt[3]{b} - {\rm{ }}\sqrt[3]{{{b^{ - 2}}}}} \right)}}$

c) $\dfrac{{{a^{\frac{1}{3}}}{b^{\frac{{ - 1}}{3}}} - {a^{\frac{{ - 1}}{3}}}{b^{\frac{1}{3}}}}}{{\sqrt[3]{{{a^2}}} - {\rm{ }}\sqrt[3]{{{b^2}}}}}$;          

d) $\dfrac{{{a^{\frac{1}{3}}}\sqrt b  + {b^{\frac{1}{3}}}\sqrt a }}{{\sqrt[6]{a} + {\rm{ }}\sqrt[6]{b}}}$