化简并求值:2(x+y)-2/3(x-y)-3(x+y)+2/3(x-y),其中x=-2,y=1详细解答!

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化简并求值:2(x+y)-2/3(x-y)-3(x+y)+2/3(x-y),其中x=-2,y=1详细解答!化简并求值:2(x+y)-2/3(x-y)-3(x+y)+2/3(x-y),其中x=-2,y=

化简并求值:2(x+y)-2/3(x-y)-3(x+y)+2/3(x-y),其中x=-2,y=1详细解答!
化简并求值:2(x+y)-2/3(x-y)-3(x+y)+2/3(x-y),其中x=-2,y=1
详细解答!

化简并求值:2(x+y)-2/3(x-y)-3(x+y)+2/3(x-y),其中x=-2,y=1详细解答!
2(x+y)-2/3(x-y)-3(x+y)+2/3(x-y)
=2(x+y) -3(x+y)-2/3(x-y) +2/3(x-y)
=-(x+y)
当x=-2,y=1时
原式=-(-2+1)=1

原式=[2(x+y)-3(x+y)]+[-2/3(x-y)+2/3(x-y)]
=-(x+y)
=-x-y
=2-1
=1

2(x+y)-2/3(x-y)-3(x+y)+2/3(x-y)
=(2-3)(x+y)+(-2/3+2/3)(x-y)
=-(x+y)
=-x-y
=-(-2)-1
=2-1
=1

原式=2(x y)-3(x y)=-x-y=1

-(x+y)=1

2(x+y)-2/3(x-y)-3(x+y)+2/3(x-y)
=(2-3)(x+y)+[(2/3)-(2/3)](x-y)
=(-1)(x+y)+0
=-(x+y)
=-x-y
=-(-2)-1
=2-1
=1