`[x+1]/[x-1]-[x-1]/[x+1]-16/[x^2-1] (x ne +-1)`

`= [(x+1)^2]/[(x-1)(x+1)]-[(x-1)^2]/[(x-1)(x+1)]-16/[(x-1)(x+1)]`

`= [x^2+2x+1-x^2+2x-1-16]/[(x-1)(x+1)]`

`= [4x-16]/[x^2-1]`