计算[(x+2y)^2-(x+y)(3x-y)-5y]/2x,其中x=-2,y=1/2

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计算[(x+2y)^2-(x+y)(3x-y)-5y]/2x,其中x=-2,y=1/2

计算[(x+2y)^2-(x+y)(3x-y)-5y]/2x,其中x=-2,y=1/2
计算[(x+2y)^2-(x+y)(3x-y)-5y]/2x,其中x=-2,y=1/2

计算[(x+2y)^2-(x+y)(3x-y)-5y]/2x,其中x=-2,y=1/2
[(x+2y)²-(x+y)(3x-y)-5y]/2x
=[(x²+4xy+4y²)-(3x²-xy+3xy+y²)-5y]/2x
=(-2x²+2xy+3y²-5y)/2x
=-x+y+3y²/2x-5y/2x
将x=-2,y=1/2代入上式得:
[(x+2y)²-(x+y)(3x-y)-5y]/2x
=2+1/2+(3/4)/(-4)+(5/2)/4
=47/16

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