分解因式：x^2y^2+xy-x^2-y^2+x+y+2
问题描述：
分解因式：x^2y^2+xy-x^2-y^2+x+y+2
答
原式=(x²y²-x²-y²+1)+(xy+x+y+1)=[x²(y²-1)-(y²-1)]+[x(y+1)+(y+1)]=(x²-1)(y²-1)+(x+1)(y+1)=(x+1)(x-1)(y+1)(y-1)+(x+1)(y+1)=(x+1)(y+1)[(x-1)(y-1)+1]=(x+1)(y+1)...