a) $\frac{11}{30}$ + $\frac{18}{35}$ . ($\frac{35}{54}$ -$\frac{49}{18}$ -$\frac{28}{48}$) b) $\frac{-23}{39}$ .$\frac{-13}{56}$ . $\frac{70}{23}$ : $\frac{125}{75}$

Đáp án + Giải thích các bước giải:

 `a,`

`11/30 + 18/35 . (35/54 - 49/18 - 28/48)`

`= 11/30 + 18/35 . (35/54 - 49/18 - 7/12)`

`= 11/30 + 18/35 . (70/108 - 294/108 - 63/108)`

`= 11/30 + 18/35 . (-287)/108`

`= 11/30 + (-41)/30`

`= -30/30 = -1`

`b,`

`(-23)/39 . (-13)/56 . 70/23 : 125/75`

`= (-23)/39 . (-13)/56 . 70/23 . 3/5`

`= (-23 . (-13) . 70 . 3)/(39 . 56 . 23 . 5)`

`= (23 . 13 . 14 . 5 . 3)/(13 . 3 . 14 . 4 . 23 . 5)`

`= 1/4`

$#datchampionforever$