Giải thích các bước giải :
`|x+1|+|x+2|+|x+3|=5x`
`+)|x+1| ≥ 0; |x+2| ≥ 0; |x+3| ≥ 0`
`=>|x+1|+|x+2|+|x+3| ≥ 0`
`=>5x ≥ 0`
`=>x ≥ 0`
`+)x ≥ 0 => |x+1| > 0 => |x+1|=x+1`
`+)x ≥ 0 => |x+2| > 0 => |x+2|=x+2`
`+)x ≥ 0 => |x+3| > 0 => |x+3|=x+3`
`+)|x+1|+|x+2|+|x+3|=5x`
`<=>x+1+x+2+x+3=5x`
`<=>3x+6=5x`
`<=>3x-5x=-6`
`<=>-2x=-6`
`<=>x=3`
Vậy `x=3`
`|2x+1|+|5x+3|=8x`
`+)|2x+1| ≥ 0; |5x+3| ≥ 0`
`=>|2x+1|+|5x+3| ≥ 0`
`=>8x ≥ 0`
`=>x ≥ 0`
`+)x ≥ 0 => |2x+1| > 0 => |2x+1|=2x+1`
`+)x ≥ 0 => |5x+3| > 0 => |5x+3|=5x+3`
`+)|2x+1|+|5x+3|=8x`
`<=>2x+1+5x+3=8x`
`<=>7x+4=8x`
`<=>7x-8x=-4`
`<=>-x=-4`
`<=>x=4`
Vậy `x=4`
