2x/x²-1=2X/x²-1
1/x+1-x/x-1={(X-1)-X((X+}/X²-1
2x/(x²-1)÷{1/(x+1)-x/(x-1)}=2X/x²-1÷{(X-1)-X((X+1)}/X²-1
=2X/(X-1)-X(X+1)
=-2X/X²+1