Đáp án:
$\dfrac{4}{5}$
Giải thích các bước giải:
$\dfrac{4}{5}×\dfrac{3}{7}+\dfrac{4}{5}×\dfrac{6}{7}-\dfrac{4}{5}×\dfrac{4}{14}$
$=\dfrac{4}{5}×\dfrac{3}{7}+\dfrac{4}{5}×\dfrac{6}{7}-\dfrac{4}{5}×\dfrac{2}{7}$
$=\dfrac{4}{5}×\bigg(\dfrac{3}{7}+\dfrac{6}{7}-\dfrac{2}{7}\bigg)$
$=\dfrac{4}{5}×\dfrac{7}{7}$
$=\dfrac{4}{5}×1$
$=\dfrac{4}{5}$
