原式=(X+Y)(X-Y)/(X-Y)^2÷Y(X+Y)/(X+Y)(X-Y)
=(X+Y)/(X-Y)÷Y(X-Y)
=(X+Y)/(X-Y)×(X-Y)/Y
=(X+Y)/Y
=X/Y+Y/Y
=2/3+1
=5/3除号后面的化简好像错了唉。。原式=(X+Y)(X-Y)/(X-Y)^2÷Y(X+Y)/X(X-Y)=(X+Y)/(X-Y)÷Y(X+Y)/X(X-Y)=(X+Y)/(X-Y)×X(X-Y)/Y(X+Y)=X/Y=2/3对不起