a)
\sqrt[3]4 * \sqrt[4]{4^2}:\sqrt4 * \sqrt[3]4^2
=4^{\frac{1}{3}} * 4^{\frac{2}{4}} : 4^{\frac{1}{2}} * 4^{\frac{2}{3}}=
4^{\frac{4+6}{12}}:4^{\frac{1}{2}}*4^{\frac{2}{3}}=
4^{\frac{5}{6}}:4^{\frac{1}{2}}*4^{\frac{2}{3}}=
4^{{\frac{5}{6}}-\frac{3}{6}}*4^{\frac{2}{3}}=4^{\frac{1}{3}+\frac{2}{3}}=4