Bài làm:
c) $\frac{4}{7}$ : ($\frac{2}{3}$ . $\frac{4}{7}$)
= $\frac{4}{7}$ : $\frac{4}{7}$ . $\frac{4}{7}$ : $\frac{2}{3}$
= 1 . $\frac{6}{7}$
= $\frac{6}{7}$
d) 5 $\frac{2}{7}$ . $\frac{8}{11}$ + 5 $\frac{2}{7}$ . $\frac{5}{11}$ - 5 $\frac{2}{7}$ . $\frac{2}{11}$
= 5 $\frac{2}{7}$ . ($\frac{8}{11}$ + $\frac{5}{11}$ - $\frac{2}{11}$)
= 5 $\frac{2}{7}$ . 1
= 5 $\frac{2}{7}$
= $\frac{37}{7}$
e) $\frac{7}{19}$ . $\frac{8}{11}$ + $\frac{7}{19}$ . $\frac{3}{11}$ = $\frac{26}{19}$
= $\frac{7}{19}$ . ($\frac{8}{11}$ + $\frac{3}{11}$) - $\frac{26}{19}$
= $\frac{7}{19}$ . 1 - $\frac{26}{19}$
= $\frac{7}{19}$ - $\frac{26}{19}$
= $\frac{-19}{19}$
Chúc bạn học tốt.
