若x-y=5,xy=6,则x^2y-xy^2=_,x^2+xy^2=__

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若x-y=5,xy=6,则x^2y-xy^2=_,x^2+xy^2=__

若x-y=5,xy=6,则x^2y-xy^2=_,x^2+xy^2=__
若x-y=5,xy=6,则x^2y-xy^2=_,x^2+xy^2=__

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

x-y=5
xy=6
x^2y-xy^2
=xy(x-y)
=5×6
=30题目是 x²+xy²x-y=5①
xy=6②
由①得:x=5+y代入②
(5+y)y=6
y²+5y-6=0
(y+6)(y-1)=0
y=-6或y=1
∴当y=-6时,x=-1,当y=1时,x=...

全部展开

x-y=5
xy=6
x^2y-xy^2
=xy(x-y)
=5×6
=30

收起

x=6, y=1
或x=-1, y=-6

x²y-xy²
=xy(x-y)
=6*5
=30

x-y=5
xy=6
解得x=6,y=1或x=-1,y=-6
x²+xy²
=x(x+y)
=6*(6+1)
=42

x²+xy²
=x(x+y)
=-1*(-1-6)
=7

可求得X为6,Y为1,当X为-1时Y为-6两种情况,将其带入可分别求得第一问有两个解30和42,第二问也有两个解42和-35