Question

Answer number 13 and please explain! Thank you.

Answer 1

$\bf \stackrel{dividend}{\cfrac{a}{3}}\div \stackrel{divisor}{\boxed{?}}=\stackrel{quotient}{\cfrac{5a^2}{6b}}\implies \cfrac{~~\frac{a}{3}~~}{\boxed{?}}=\cfrac{5a^2}{6b}\implies \stackrel{cross-multiplying}{6b\left( \cfrac{a}{3} \right)=\boxed{?}(5a^2)} \\\\\\ 2ab=\boxed{?}5a^2\implies \cfrac{2ab}{5a^2}=\boxed{?}\implies \cfrac{2b}{5a}=\boxed{?} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill \cfrac{a}{3}~~\div~~\cfrac{2b}{5a}~\hfill$