a,-3/8:(4/-7.21/-22) b,5/7.(2/-3+-7/8) c,3/-4:(12/-5- -7/10)

Đáp án:

`a,``(-3)/8:(4/(-7). 21/(-22))`

`=  (-3)/8: 6/11`

`= (-3)/8 . 11/6`

`= (-11)/16`

`b,` `5/7.(2/[-3]+[-7]/8)`

`= 5/7 . (-37)/24`

`= (-185)/168`

`c,` `3/(-4) : (12/(-5) - (-7)/10)`

`= 3/(-4) : (-17)/10`

`= 3/(-4) xx 10/(-17)`

`= 15/34`  

$#dariana$

#andy

\[\begin{array}{l}
a)\dfrac{{ - 3}}{8}:\left( {\dfrac{4}{{ - 7}}.\dfrac{{21}}{{ - 22}}} \right)\\
 = \;\dfrac{{ - 3}}{8}:\dfrac{6}{{11}}\\
 = \dfrac{{ - 11}}{{16}}\\
b)\dfrac{5}{7}.\left( {\dfrac{2}{{ - 3}} + \dfrac{{ - 7}}{8}} \right)\\
 = \dfrac{5}{7}.\dfrac{{ - 37}}{{24}}\\
 = \dfrac{{ - 185}}{{168}}\\
c)\dfrac{3}{{ - 4}}:\left( {\dfrac{{12}}{{ - 5}} - \dfrac{{ - 7}}{{10}}} \right)\\
 = \dfrac{3}{{ - 4}}:\dfrac{{ - 17}}{{10}}\\
 = \dfrac{{15}}{{34}}
\end{array}\]