a) $\frac{24 × 47 - 23}{23 × 47 + 24} × \frac{3 + \frac{3}{7} - \frac{3}{11}- \frac{3}{13}+\frac{3}{2020}}{\frac{9}{11}- \frac{9}{7} + \frac{9}{13}-\frac{9}{2020}-9}$
$=\frac{23 × 47 + 47 - 23}{23 ×47 + 24}×\frac{3 + \frac{3}{7} - \frac{3}{11}- \frac{3}{13}+\frac{3}{2020}}{-3(3 + \frac{3}{7} - \frac{3}{11}- \frac{3}{13}+\frac{3}{2020})}$
$=\frac{23 × 47 + 24}{23 ×47 + 24}×\frac{1}{-3}$
$=1×\frac{-1}{3}$
$=\frac{-1}{3}$
Bạn tham khảo nhé.
