`[x+2]/[x-2]-1/x=2/[x^2-2x]` `ĐK: x \ne 0,x \ne 2`
`<=>[x(x+2)]/[x(x-2)]-[x-2]/[x(x-2)]=2/[x(x-2)]`
`=>x^2+2x-x+2=2`
`<=>x^2+x=0`
`<=>x(x+1)=0`
`<=>` $\left[\begin{matrix} x=0\\ x+1=0\end{matrix}\right.$
`<=>` $\left[\begin{matrix} x=0\text{ (ko t/m)}\\ x=-1\text{ (t/m)}\end{matrix}\right.$
Vậy `S={-1}`