Tính nhanh: g) $(\frac{-17}{209}+\frac{8}{753}-\frac{9}{1231}).(\frac{-3}{5}-\frac{3}{4}+\frac{27}{20})$ h) $\frac{2}{1.4}+\frac{2}{4.7}+\frac{2}{7.10}+...+\frac{2}{301.204}$

`g ) ((-17)/209 + 8/753 - 9/1231) . ((-3)/5 - 3/4 + 27/20)`

`= ((-17)/209 + 8/753 - 9/1231) . ((-12)/20 + (-15)/20 + 27/20)`

`= ((-17)/209 + 8/753 - 9/1231) . 0`

`= 0`

`h ) 2/(1.4) + 2/(4.7) + 2/(7.10) + ... + 2/(301.304)`

`= 2/3 . (3/(1.4) + 3/(4.7) + 3/(7.10) + ... + 3/(301.304))`

`= 2/3 . (1/1 - 1/4 + 1/4 - 1/7 + 1/7 - 1/10 + ... + 1/301 - 1/304)`

`= 2/3 . (1/1 - 1/304)`

`= 2/3 . 303/304`

`= 101/152`

`#dtkc`