若x—y=2009,xy=—1,则-X^2y+xy^2=
问题描述:
若x—y=2009,xy=—1,则-X^2y+xy^2=
答
-X^2y+xy^2
=-xy(x-y)
=2009
若x—y=2009,xy=—1,则-X^2y+xy^2=
-X^2y+xy^2
=-xy(x-y)
=2009