问题 填空题 2xy-y2x2-y2+x-yx+y=mx2-y2,则m=______. 答案 ∵2xy-y2x2-y2+x-yx+y=mx2-y2,∴2xy-y2x2-y2+(x-y)2x2-y2=x2x2-y2.故答案为:x2.