[tex]\bf a^{\frac{{ n}}{{ m}}} \implies \sqrt[{ m}]{a^{ n}} \qquad \qquad
\sqrt[{ m}]{a^{ n}}\implies a^{\frac{{ n}}{{ m}}}\\\\
-----------------------------\\\\
\sqrt[5]{(x^7)^3}\implies \sqrt[5]{x^{7\cdot 3}}\implies \sqrt[5]{x^{21}}\implies x^{\cfrac{}{}\frac{21}{5}}[/tex]
