trình bày rõ ràng ạ ;-; So sánh: a) $\frac{-109}{111}$ và $\frac{205}{-207}$ b) $\frac{-252}{197}$ và $\frac{-231}{203}$

a) Ta có : +) $\dfrac{-109}{111}$ = -1 - $\dfrac{-2}{111}$ 

+) $\dfrac{205}{-207}$ = -1 - $\dfrac{-2}{207}$ 

Do $\dfrac{2}{111}$ > $\dfrac{2}{207}$ nên $\dfrac{-2}{111}$  < $\dfrac{-2}{207}$ hay $\dfrac{-109}{111}$< $\dfrac{205}{-207}$ 

Vậy $\dfrac{-109}{111}$< $\dfrac{205}{-207}$ 

b) $\dfrac{-252}{197}$ < $\dfrac{-252}{203}$ < $\dfrac{-231}{203}$ nên $\dfrac{-252}{197}$ < $\dfrac{-231}{203}$

Vậy $\dfrac{-252}{197}$ < $\dfrac{-231}{203}$