Đáp án:
a)$\dfrac{776}{1455}$ - $\dfrac{-392}{1470}$
= $\dfrac{8}{15}$ - $\dfrac{-4}{15}$
= $\dfrac{4}{15}$
b) $\dfrac{-32}{144}$ - $\dfrac{-95}{152}$
= $\dfrac{-2}{9}$ - $\dfrac{-5}{8}$
= $\dfrac{-2.8}{9.8}$ - $\dfrac{-5.9}{8.9}$
= $\dfrac{-16}{72}$ - $\dfrac{-45}{72}$
= $\dfrac{-61}{72}$
Giải thích các bước giải: