a) `3/14 x - 1/4 = 2(x-3) + 1/4x`
`=> 3/14 x - 1/4 = 2x -6 + 1/4x`
`=> 3/14 x - 2x - 1/4 x = -6 + 1/4`
`=> (3/14 -2-1/4) x = -23/4`
`=>-57/28 x = -23/4`
`=> x= (-23/4) : (-57/28)`
`=> x= -23/4 . (-28/57)`
`=> x= 161/57`
Vậy `x= 161/57`
b) `30% x - x +5/6 = 1/3`
`=> 3/10 x - x = 1/3 - 5/6`
`=> (3/10 -1) x = -1/2`
`=> -7/10 x = -1/2`
`=> x= -1/2 : (-7/10)`
`=> x= -1/2 . (-10/7)`
`=> x=5/7`
Vậy `x= 5/7`