Đáp án:
Giải thích các bước giải:
a)= ($\frac{1}{4}$ + $\frac{-5}{13}$ ) + ($\frac{2/11}{y}$ + $\frac{-8}{13}$ +$\frac{3}{4}$ )
= $\frac{1}{4}$ + $\frac{-5}{13}$ + $\frac{2}{11}$ + $\frac{-8}{13}$ + $\frac{3}{4}$
= ($\frac{1}{4}$ + $\frac{3}{4}$ ) + ( $\frac{-5}{13}$ + $\frac{-8}{13}$) + $\frac{2}{11}$
=1 +-1 +$\frac{2}{11}$
= 0
b) = ($\frac{21}{31}$ +$\frac{-16}{7}$) + ($\frac{44}{53}$ + $\frac{10}{31}$ ) + $\frac{9}{53}$
= $\frac{21}{31}$ + $\frac-{-16}{7}$ + $\frac{44}{53}$ + $\frac{10}{31}$ + $\frac{9}{53}$
= ($\frac{21}{31}$ + $\frac{10}{31}$ ) + ( $\frac{44}{53}$ + $\frac{9}{53}$ ) + $\frac{-16}{7}$
= 1 + 1 + $\frac{-16}{7}$
= $\frac{14}{7}$ + $\frac{-16}{7}$
= $\frac{2}{7}$
c) = $\frac{-5}{7}$ + $\frac{3}{4}$ + $\frac{-1}{5}$ + $\frac{-2}{7}$ + $\frac{1}{4}$
= ($\frac{-5}{7}$ + $\frac{-2}{7})$ + ($\frac{3}{4}$ + $\frac{1}{4}$) + $\frac{-1}{5}$
= -1 + 1 + $\frac{-1}{5}$
= $\frac{-1}{5}$
d) = $\frac{-3}{31}$ +$\frac{-6}{17}$ +$\frac{1}{25}$ +$\frac{-28}{31}$ +$\frac{-11}{17}$ +$\frac{-1}{5}$
= ($\frac{-3}{31}$ +$\frac{-28}{31}$) +($\frac{-6}{17}$ +$\frac{-11}{17}$) +($\frac{1}{25}$ +$\frac{-1}{5}$)
= -1 + -1 + $\frac{-4 }{25}$
= $\frac{-50}{25}$ +$\frac{-4}{25}$
= $\frac{-54}{25}$
