Applicare la formula: $\frac{a^m}{a^n}$$=a^{\left(m-n\right)}$, dove $a^n=y^{-\frac{7}{9}}$, $a^m=y^{-\frac{2}{3}}$, $a=y$, $a^m/a^n=\frac{\sqrt[3]{x}y^{-\frac{2}{3}}}{\sqrt[3]{x^{4}}y^{-\frac{7}{9}}}$, $m=-\frac{2}{3}$ e $n=-\frac{7}{9}$

Applicare la formula: $\frac{a^m}{a^n}$$=\frac{1}{a^{\left(n-m\right)}}$, dove $a=x$, $m=\frac{1}{3}$ e $n=\frac{4}{3}$

Applicare la formula: $\frac{a}{b}$$=\frac{a}{b}$, dove $a=3$, $b=3$ e $a/b=\frac{3}{3}$