Applicare la formula: $\frac{a}{a}$$=1$, dove $a=b^9$ e $a/a=\frac{10a^7b^9}{15a^5b^9}$

Applicare la formula: $\frac{a^m}{a^n}$$=a^{\left(m-n\right)}$, dove $a^n=a^5$, $a^m=a^7$, $a^m/a^n=\frac{10a^7}{15a^5}$, $m=7$ e $n=5$

Applicare la formula: $\frac{ab}{c}$$=\frac{a}{c}b$, dove $ab=10a^{2}$, $a=10$, $b=a^{2}$, $c=15$ e $ab/c=\frac{10a^{2}}{15}$