x2+2xy+y2x2y+xy2−x2−2xy+y2x2y−xy2.

问题描述:

x2+2xy+y2
x2y+xy2
x2−2xy+y2
x2y−xy2

原式=

(x+y)2
xy(x+y)
-
(x−y)2
xy(x−y)

=
x+y
xy
-
x−y
xy

=
x+y−x+y
xy

=
2y
xy

=
2
x