$\frac{3x}{8}\ast <!--\; \ast \; -->\frac{4}{9y}=\frac{x}{2}\ast <!--\; \ast \; -->\frac{1}{3y}=\frac{x}{6y}$

$\frac{8mn}{15}\ast <!--\; \ast \; -->\frac{25k}{32m}=\frac{n}{3}\ast <!--\; \ast \; -->\frac{5k}{4}=\frac{5kn}{12}$

$\frac{7a}{8b}\ast <!--\; \ast \; -->\frac{8b}{7a}=\frac{1}{1}\ast <!--\; \ast \; -->\frac{1}{1}=1$

$\frac{24xy}{17z}\ast <!--\; \ast \; -->\frac{34z}{15y}=\frac{8x}{1}\ast <!--\; \ast \; -->\frac{2}{5}=\frac{16x}{5}=3\frac{x}{5}$