Câu 2:
a) `7/8 + 2,5 x = 5/6`
`2,5 x = 5/6 - 7/8`
`5/2 x= -1/24`
`x= -1/24 : 5/2`
`x= -1/24 . 2/5`
`x= -1/60`
Vậy `x= -1/60`
b) `2( x - 1/3) = 5/9`
`x -1/3 = 5/9 : 2`
`x-1/3= 5/9 . 1/2`
`x- 1/3 =5/18`
`x= 5/18 + 1/3`
`x= 11/18`
Vậy `x= 11/18`
c) `4- ( 1/2 x + 3/4) = -1,5`
`4- 1/2 x - 3/4 = -3/2`
`13/4 - 1/2 x = -3/2`
`1/2 x= 13/4 - (-3/2)`
`1/2 x = 13/4 + 3/2`
`1/2 x= 19/4`
`x= 19/4 : 1/2`
`x= 19/4 . 2`
`x=19/2`
Vậy `x= 19/2`