因式分解
(x+y)(x+y+2xy)+(xy+1)(xy-1)
参考答案:原式=(x+y)(x+y)+2(x+y)xy+(xy)^2-1^2
=(x+y)^2+2(x+y)xy+(xy)^2-1
=(x+y+xy)^2-1
=(x+y+xy-1)(x+y+xy+1)
=(x+y+xy-1)(x+1)(y+1)
(x+y)(x+y+2xy)+(xy+1)(xy-1)
参考答案:原式=(x+y)(x+y)+2(x+y)xy+(xy)^2-1^2
=(x+y)^2+2(x+y)xy+(xy)^2-1
=(x+y+xy)^2-1
=(x+y+xy-1)(x+y+xy+1)
=(x+y+xy-1)(x+1)(y+1)