$@Mốc$
a) $\frac{2}{3}$ - $4$.($\frac{1}{2}$ + $\frac{3}{4}$)
= $\frac{2}{3}$ - $4$.($\frac{2}{4}$ + $\frac{3}{4}$)
= $\frac{2}{3}$ - $4$.$\frac{5}{4}$
= $\frac{2}{3}$ - $5$
= $\frac{2}{3}$ - $\frac{15}{3}$
= $\frac{-13}{3}$
b) ($\frac{5}{7}$ - $\frac{7}{5}$) - [$\frac{1}{2}$ - ($\frac{-2}{7}$ - $\frac{1}{10}$)]
= ($\frac{25}{35}$ - $\frac{49}{35}$) - [$\frac{1}{2}$ + $\frac{2}{7}$ + $\frac{1}{10}$]
= $\frac{-24}{35}$ - [$\frac{70}{140}$ + $\frac{40}{140}$ + $\frac{14}{10}$]
= $\frac{-24}{35}$ - $\frac{124}{140}$
= $\frac{-96}{140}$ - $\frac{124}{140}$
= $\frac{-220}{140}$
= $\frac{-11}{7}$
$#chucbanhoctotnhe;333$
