已知x+y=3,xy=0.5,求(1)2x²y+2xy²的值;(2)x²+y²的
3个回答
(1)
2x²y+2xy²
=2xy(x+y)
=2*0.5*3
=3
(2)
x²+y²
=(x+y)²-2xy
=3²-2*0.5
=9-1
=8
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