Đáp án:
Giải thích các bước giải:
a,
=($\frac{-2}{3}$+$\frac{3}{7}$) $\frac{5}{4}$ +($\frac{-1}{3}$+ $\frac{4}{7}$ )$\frac{5}{4}$
=$\frac{5}{4}$( $\frac{-2}{3}$+ $\frac{-1}{3}$+ $\frac{3}{7}$+ $\frac{4}{7}$
=$\frac{5}{4}$(-1+1)
=$\frac{5}{4}$.0=0
b,
=$\frac{5}{9}$:( $\frac{2}{22}$- $\frac{5}{22}$ ) +$\frac{5}{9}$:( $\frac{1}{15}$ - $\frac{10}{15}$)
=$\frac{5}{9}$: $\frac{-3}{22}$+ $\frac{5}{9}$: $\frac{-3}{5}$
=$\frac{5}{9}$.$\frac{22}{-3}$+ $\frac{5}{9}$. $\frac{5}{-3}$
=$\frac{5}{9}$( $\frac{22}{-3}$+ $\frac{5}{-3}$
=$\frac{5}{9}$. $\frac{27}{-3}$ = $\frac{5}{9}$.(-9)=-5
