Question

求怎样因式分解？

Answer 1

图

追答

Answer 2

(xy+1)(x+1)(y+1)+xy
=(xy+1)(xy+x+y+1)+xy
=x^2y^2+x^2y+xy^2+xy+xy+x+y+1+xy
=x^2y^2+x^2y+xy^2+3xy+x+y+1
=x^2y^2+x^2y+xy+xy^2+xy+y+xy+x+1
=xy(xy+x+1)+y(xy+x+1)+xy+x+1
=(xy+x+1)(xy+y+1)