3xy²-2(xy-3/2x²y)+(3x²y-2xy²),其中,x=-2,y=1/2挺急的,答对再追加10、先化简，再求值

3xy²-2(xy-3/2x²y)+(3x²y-2xy²),其中,x=-2,y=1/2挺急的,答对再追加10、先化简，再求值
3xy²-2(xy-3/2x²y)+(3x²y-2xy²),其中,x=-2,y=1/2
挺急的,答对再追加10、
先化简，再求值

3xy²-2(xy-3/2x²y)+(3x²y-2xy²),其中,x=-2,y=1/2挺急的,答对再追加10、先化简，再求值
解原式
=3xy²-2(xy-3/2x²y)+(3x²y-2xy²)
=3xy²-2xy+3x²y+3x²y-2xy²
=xy²+6x²y-2xy
=xy(y+6x-2）
=（-2）×（1/2)[1/2+6×（-2）-2]
=-（1/2-14)
=14-1/2
=27/2

=3xy²-2xy+3x²y+3x²y-2xy²
=(3xy²-2xy²)-2xy+(3x²y+3x²y)
=xy²-2xy+6x²y
=xy(y-2+6x)
=-2×1/2(1/2-2-12)
=-(1/2-14)
=13又2分之1还有一题，已知2x...

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=3xy²-2xy+3x²y+3x²y-2xy²
=(3xy²-2xy²)-2xy+(3x²y+3x²y)
=xy²-2xy+6x²y
=xy(y-2+6x)
=-2×1/2(1/2-2-12)
=-(1/2-14)
=13又2分之1

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