若x-y=5,xy=6,则x^2y-xy^2=_,x^2+xy^2=__

问题描述:

若x-y=5,xy=6,则x^2y-xy^2=_,x^2+xy^2=__

第1小题:
x²y-xy²
=xy(x-y)
=6(5)
=30
第2小题:
(x+y)²
=x²+y²+2xy
=x²+y²-2xy+4xy
=(x-y)²+4xy
=5²+24
=49
x+y=7或x+y=-7.
x²y+xy² (第二小题的题目应该是这样的吧)
=xy(x+y)
=6(7)
=42
或:
x²y+xy²
=xy(x+y)
=6(-7)
=-42