Question

用双十字相乘法,xy+y^2+x-y-2,

Answer 1

xy＋y²＋x－y－2

=y(x＋y)＋(x－y)－2

y 1

x＋y －2

则：xy＋y²＋x－y－2=(x＋1)[(x＋y)－2]=(x＋1)(x＋y－2)