Remember that $\displaystyle{{a}}^{{\frac{{1}}{{3}}}}={\sqrt[{{3}}]{{{a}}}}\usepackage{cmbright}\Huge\$ , so $\displaystyle{{5}}^{{\frac{{7}}{{3}}}}={{\left({{5}}^{{7}}\right)}}^{{\frac{{1}}{{3}}}}={\sqrt[{{3}}]{{{{5}}^{{7}}}}}\usepackage{cmbright}\Huge\$ . How do we simplify the radical?