Ответ :
[tex] \\\frac{a^{-3}\cdot a^{\frac{7}{3}}}{a^{\frac{1}{3}}}=\\ \frac{a^{-3+\frac{7}{3}}}{a^{\frac{1}{3}}}=\\ \frac{a^{-\frac{9}{3}+\frac{7}{3}}}{a^{\frac{1}{3}}}=\\ \frac{a^{-\frac{2}{3}}}{a^{\frac{1}{3}}}=\\ a^{-\frac{2}{3}-\frac{1}{3}}=\\ a^{-\frac{3}{3}}=\\ a^{-1}=\\ \frac{1}{a}=\\\frac{1}{a^2}[/tex]