$a,\frac{-150}{90}$ $;\frac{120}{600}$ $;\frac{-75}{150}$
Ta có:
$\frac{120}{600}=$ $\frac{1}{5}$$=\frac{-5}{30}$
$\frac{-15}{90}=$ $\frac{-1}{6}$ $=\frac{6}{30}$
$\frac{-75}{150}=$ $\frac{-1}{2}$$=\frac{-15}{30}$
$b,\frac{54}{-90}$$;\frac{-150}{288}$$;\frac{60}{-135}$
$\frac{54}{-90}=$ $\frac{-3}{5}=$ $\frac{-432}{720}$
$\frac{-150}{288}=$ $\frac{-25}{48}=$$\frac{-375}{720}$
$\frac{60}{-135}=$ $\frac{-4}{9}=$$\frac{-320}{720}$