giúp mik làm bài này với

`a)18/19 .x=36`

`=>x=36: 18/19`

`=>x=36. 19/18`

`=>x=(18.2.19)/18`

`=>x=38`

`b)15/31 .x=225`

`=>x=225: 15/31`

`=>x=225. 31/15`

`=>x=(15.15.31)/15`

`=>x=465`

`c)11/19 .x=45`

`=>x=45: 11/19`

`=>x=45. 19/11`

`=>x=855/11`

`d)6/7 .x=18/23`

`=>x=18/23 : 6/7`

`=>x=18/23 . 7/6`

`=>x=(6.3.7)/(23.6)`

`=>x=21/23`

`e)2 1/2 .x=5/6`

`=>5/2 .x=5/6`

`=>x=5/6 : 5/2`

`=>x=5/6 . 2/5`

`=>x=(5.2)/(2.3.5)`

`=>x=1/3`

`g)x:2 3/4=9 5/8`

`=>x:11/4=77/8`

`=>x=77/8 . 11/4`

`=>x=847/32`

`h)7 1/7 . 1/7 .x=22 1/8`

`=>50/7 . 1/7 .x=177/8`

`=>50/49 .x=177/8`

`=>x=177/8 : 50/49`

`=>x=177/8 . 49/50`

`=>x=8673/400`