Đáp án+Giải thích các bước giải:
a)$\frac{-1}{4}$+$\frac{-5}{4}$= $\frac{-6}{4}$ =$\frac{-3}{2}$
b)$\frac{-3}{10}$ :$\frac{-2}{5}$ =$\frac{-3}{10}$ . $\frac{-5}{2}$= $\frac{3}{4}$
c)`1`$\frac{2}{3}$ . $\frac{-27}{10}$=$\frac{5}{3}$ . $\frac{-27}{10}$ = $\frac{-9}{2}$
d)$\frac{-11}{4}$ . $\frac{2}{7}$ + $\frac{-11}{4}$ . $\frac{5}{7}$ =$\frac{-11}{4}$ .($\frac{2}{7}$ + $\frac{5}{7}$) =$\frac{-11}{4}$ . $\frac{7}{7}$ = $\frac{-11}{4}$.`1` =$\frac{-11}{4}$