`#0409`

`a,`

`3-0,2x<13`

`-0,2x<-3+13`

`-0,2x<10`

`x> -50`

Vậy `S={x|x> -50}`

`b,`

`1/2+x/3>=1/4`

`x/3>=1/4-1/2`

`x/3>=-1/4`

`(4x)/12>=-3/12`

Suy ra `:4x>=-3`

`x>=-3/4`

Vậy `S={x|x>=-3/4}`

`c,`

`3<(2x-2)/8`

`24/8<(2x-2)/8`

Suy ra `:` `24<2x-2`

`-2x<-24-2`

`-2x<-26`

`x>13`

Vậy `S={x|x>13}`

`d,`

`(2x-3)/3<=(3x-2)/4`

`(4(2x-3))/12<=(3(3x-2))/12`

Suy ra `4(2x-3)<=3(3x-2)`

`8x-12<=9x-6`

`8x-9x<=12-6`

`-x<=6`

`x>=-6`

Vậy `S={x|x>=-6}`