先化简,再求值：{（xy-2）^2+4xy-4}/(-xy),其中x=1.,y=-1/25

{（xy-2）^2+4xy-4}/(-xy)={(xy-2)^2+2(xy-2)+1+2xy-1}/(-xy)={[(xy-2)+1]^2+2xy-1}/(-xy)={(xy-1)^2+2xy-1}/(-xy)={(xy)^2-2xy+1+2xy-1}/(-xy)=(xy)^2/(-xy)=-xy=-1*(-1/25)=1/25