GIẢI

1 .`(x - 1)/5 - (4x + 3)/10 < 1 - (5x)/25`

`(2(x - 1) - (4x + 3))/10 < 1 - x/5`
`(2x - 2 - 4x - 3)/10 < 1 - x/5`
`(-2x - 5)/10 < 1 - x/5`

`-2x - 5 < 10 - 2x`

`-5 < 10  ` (luôn đúng)

2. `(x + 2)/4 + (2x - 3)/3 < (x - 12)/6`

`(3(x + 2) + 4(2x - 3))/12 < (x - 12)/6`
`(3x + 6 + 8x - 12)/12 < (x - 12)/6`
`(11x - 6)/12 < (x - 12)/6`

`11x - 6 < 2(x - 12)`
`11x - 6 < 2x - 24`
`9x < -18`
`x < -2`

3.`(3x + 5)/4 - (x - 4)/6 < (3x + 7)/3`

`(3(3x + 5) - 2(x - 4))/12 < 4(3x + 7)/12`
`(9x + 15 - 2x + 8)/12 < (12x + 28)/12`
`(7x + 23)/12 < (12x + 28)/12`
`7x + 23 < 12x + 28`
`23 < 5x + 28`
`-5 < 5x`
`x > -1`