Giải hộ mik câu 21 vs 22 nhe

Đáp án:

 21, $0$

22, $14

Giải thích các bước giải:

21,
$(\dfrac{5}{3}-\dfrac{3}{7}+9)-(2+\dfrac{5}{7}-\dfrac{2}{3})+(\dfrac{8}{7}-\dfrac{4}{3}-10)$
$=(\dfrac{5}{3}+\dfrac{2}{3}-\dfrac{4}{3})+(9-2-10)+(\dfrac{8}{7}-\dfrac{3}{7}-\dfrac{5}{7})$
$=\dfrac{5+2-4}{3}-1+\dfrac{8-3-5}{7}=0$
22,
$\dfrac{\dfrac{1}{9}-\dfrac{1}{7}-\dfrac{1}{11}}{\dfrac{4}{9}-\dfrac{4}{7}-\dfrac{4}{11}}+\dfrac{\dfrac{3}{5}-\dfrac{3}{25}-\dfrac{3}{125}-\dfrac{3}{625}}{\dfrac{4}{5}-\dfrac{4}{25}-\dfrac{4}{125}-\dfrac{4}{625}}$
$=\dfrac{\dfrac{1}{9}-\dfrac{1}{7}-\dfrac{1}{11}}{4(\dfrac{1}{9}-\dfrac{1}{7}-\dfrac{1}{11})}+\dfrac{3(\dfrac{1}{5}-\dfrac{1}{25}-\dfrac{1}{125}-\dfrac{1}{625})}{4(\dfrac{1}{5}-\dfrac{1}{25}-\dfrac{1}{125}-\dfrac{1}{625})}$
$=\dfrac{1}{4}+\dfrac{3}{4}=1$