Answer :
[tex]\frac{1}{2}\cdot\frac{\not5}{\not8_2}\cdot\frac{\not4}{\not5}=\frac{1}{2}\cdot\frac{1}{2}\cdot\frac{1}{1}=\frac{1}{2\cdot2}=\boxed{\frac{1}{4}}\\\\-\frac{\frac{3}{8}}{\frac{3}{4}}=-\frac{3}{8}:\frac{3}{4}=-\frac{\not3}{8}\times\frac{4}{\not3}=-\frac{4}{8}=\boxed{-\frac{1}{2}}\\\\-\frac{\frac{16}{9}}{8}=-\frac{16}{9}:8=-\frac{\not16^2}{9}\times\frac{1}{\not8}=\boxed{-\frac{2}{9}}[/tex]
