3x^2y-(6xy-2(4xy-2)-x^2y)+1,其中x=-2分之1.结果等于-3,没有写出y等于几

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3x^2y-(6xy-2(4xy-2)-x^2y)+1,其中x=-2分之1.结果等于-3,没有写出y等于几
3x^2y-(6xy-2(4xy-2)-x^2y)+1,其中x=-2分之1.结果等于-3,没有写出y等于几

3x^2y-(6xy-2(4xy-2)-x^2y)+1,其中x=-2分之1.结果等于-3,没有写出y等于几
3x²y－[6xy－2﹙4xy－2﹚－x²y]＋1
=3x²y－[6xy－8xy＋4－x²y]＋1
=3x²y－[－2xy＋4－x²y]＋1
=3x²y＋2xy－4＋x²y＋1
=4x²y＋2xy－3
当x=－1／2时,原式=4×﹙－1／2﹚²·y＋2×﹙－1／2﹚·y－3
=y－y－3
=－3
希望对你有用!


3x^2y-(6xy-2(4xy-2)-x^2y)+1
=3x^2y-6xy+2(4xy-2)+x^2y+1
=3x^2y-6xy+8xy-4+x^2y+1
=4x^2y+2xy-3
依题意，当x=-1/2时，上式的值是-3，
即：
4(-1/2)^2y+2(-1/2)y-3=-3
y-y=0
0-0
可见，不管y为何值，当x=-1/2时，恒有：原式=-3

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