Question

因式分解:(x+y-2xy)(x+y-2)+(xy-1)^2

Answer 1

=[(x+y)-2xy][(x+y)-2]+(xy-1)^2

=(x+y)^2-2(x+y)(xy+1)+4xy+(xy-1)^2

=(x+y)^2-2(x+y)(xy+1)+(xy+1)^2

=(x+y-xy-1)^2