a)
[tex]\mathrm{Aplicar\:las\:propiedades\:de\:las\:fracciones}:\quad \frac{a}{b}\div \frac{c}{d}=\frac{a}{b}\times \frac{d}{c}\\\\\\=\frac{6}{9}\times \frac{8}{1}\\\\\\=\frac{2}{3}\times \frac{8}{1}\\=8\times \frac{2}{3}\\=\frac{16}{3\times \:1}\\\\=\frac{16}{3}[/tex]
b)[tex]\frac{3}{5}\div \frac{2}{5}=\frac{3}{2}[/tex]
c)[tex]\frac{1}{6}\div \frac{2}{3}=\frac{1}{4}[/tex]
d)[tex]\frac{3}{9}\div \frac{2}{4}=\frac{2}{3}[/tex]
listo
