Đáp án+Giải thích các bước giải:
`|5x-4|=|x+2|`
`->(5x-4)^2=(x+2)^2`
`->(5x-4)(5x-4)=(x+2)(x+2)`
`->25x^2-40x+16=x^2+4x+4`
`->25x^2-40x+16-x^2-4x-4=0`
`->(25x^2-x^2)-(40x+4x)+(16-4)=0`
`->24x^2-44x+12=0`
`->x^2-11/6x+1/2=0`
`->x^2-2 . 11/12 x+(11/12)^2-49/144=0`
`->(x-11/12)^2=49/144`
`->|x-11/12|=7/12`
`TH1: x - 11/12=7/12`
`->x=7/12+11/12`
`->x=3/2`
`TH2: x - 11/12=-7/12`
`->x=-7/12+11/12`
`->x=1/3`
Vậy `S={1/3;3/2}`
