作业帮xy-2y²-2[4xy-（3y²-x²y）+5（-3y²+2/5 x²y）],其中x=1,y=-2．
来源：学生作业帮助网 编辑：作业帮 时间：2024/11/24 00:09:49
![xy-2y²-2[4xy-（3y²-x²y）+5（-3y²+2/5 x²y）],其中x=1,y=-2．](/uploads/image/z/3779887-31-7.jpg?t=xy-2y%26%23178%3B-2%5B4xy-%EF%BC%883y%26%23178%3B-x%26%23178%3By%EF%BC%89%2B5%EF%BC%88-3y%26%23178%3B%2B2%2F5+x%26%23178%3By%EF%BC%89%5D%2C%E5%85%B6%E4%B8%ADx%3D1%2Cy%3D-2%EF%BC%8E)
xy-2y²-2[4xy-（3y²-x²y）+5（-3y²+2/5 x²y）],其中x=1,y=-2．
xy-2y²-2[4xy-（3y²-x²y）+5（-3y²+2/5 x²y）],其中x=1,y=-2．
xy-2y²-2[4xy-（3y²-x²y）+5（-3y²+2/5 x²y）],其中x=1,y=-2．
xy-2y²-2[4xy-（3y²-x²y）+5（-3y²+2/5 x²y）]
=xy-2y²-2(4xy-3y²+x²y-15y²+2x²y)
=xy-2y²-2(4xy-18y²+3x²y)
=xy-2y²-8xy+36y²-6x²y
=y(x-2y-8x+36y-6x²)
=-2(1+4-8-72-6)
=162
xy-2y²-2[4xy-（3y²-x²y）+5（-3y²+2/5 x²y）]
=xy-2y²-2[4xy-3y²+x²y-15y²+2x²y]
=xy-2y²-2[4xy-3y²-15y²+x²y+2x²y]
=xy-2y&...
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xy-2y²-2[4xy-（3y²-x²y）+5（-3y²+2/5 x²y）]
=xy-2y²-2[4xy-3y²+x²y-15y²+2x²y]
=xy-2y²-2[4xy-3y²-15y²+x²y+2x²y]
=xy-2y²-2[4xy-18y²+3x²y]
=xy-2y²-8xy+36y²-6x²y
=xy-8xy-2y²+36y²-6x²y
=-7xy+34y²-6x²y
=-7*1*(-2)+34*(-2)²-6*1²*(-2)
=14+136+12
=162
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xy-2y²-2[4xy-（3y²-x²y）+5（-3y²+2/5 x²y）]
=xy-2y²-2[4xy-3y²+x²y-15y²+2x²y]
=xy-2y²-2(4xy-18y²+3x²y)
=xy-2y²-8xy+36y²-6x²y
=34y²-7xy-6x²y
=34×4+7×1×2+6×1×2
=136+26
=162