当x=3,y=-1/3时,求多项式3x²y-[2xy²-2(xy-3/2x²y)+xy]+3xy²的值
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当x=3,y=-1/3时,求多项式3x²y-[2xy²-2(xy-3/2x²y)+xy]+3xy²的值
当x=3,y=-1/3时,求多项式3x²y-[2xy²-2(xy-3/2x²y)+xy]+3xy²的值
当x=3,y=-1/3时,求多项式3x²y-[2xy²-2(xy-3/2x²y)+xy]+3xy²的值
原式=3X²Y-2XY²+2XY-3X²Y-XY+3XY²
=(3-3)X²Y+(3-2)XY²+(2-1)XY
=XY²+XY
=XY(Y+1)
∵X=3 Y=-1/3
∴原式=3×(-1/3)(-1/3+1)
=-1×2/3
=-2/3
原式=xy2+xy
=1/3-1
=-2/3