`(46-x)/(167)+(135-3x)/(504)-(381+3x)/(510)+(88-2x)/(338)+5=0`
`⇔((46-x)/(167)+1)+((135-3x)/(504)+1)-((381+3x)/(510)-2)+((88-2x)/(338)+1)=0`
`⇔(213-x)/(167)+(3.(213-x))/(504)+(3.(213-x))/(510)+(2.(213-x))/(338)=0`
`⇔(213-x).(1/(167)+(3)/(504)+(3)/(510)+(2)/(338))=0`
`⇔213-x=0` (do `1/(167)+(3)/(504)+(3)/(510)+(2)/(338)\ne0`)
`⇔x=213`
Vậy `S={213}`.