$#Dino$
`(x+1)/(x+2)-x/(x-2)=(2x-3)/(x²-4)`
`ĐKXĐ:x`$\neq$ `±2`
`⇔((x-2)(x+1))/(x²-4)-(x(x+2))/(x²-4)=(2x-3)/(x²-4)`
`⇒(x-2)(x+1)-x(x+2)=2x-3`
`⇒x²+x-2x-2-x²-2x-2x=3`
`⇔-5x=5`
`⇔x=-1`
Vậy `S={-1}`
`b)(2x-1)/4+(x-3)/6=1`
`⇔(6(2x-1))/24+(4(x-3))/24=24/24`
`⇔12x-6+4x-12=24`
`⇔16x=42`
`⇔x=42/16=21/8`
Vậy `S={21/8}`