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

Applicare la formula: $\frac{a}{\frac{b}{c}}$$=\frac{ac}{b}$, dove $a=x^{2}$, $b=2$, $c=7$, $a/b/c=\frac{x^{2}}{\frac{2}{7}}$ e $b/c=\frac{2}{7}$