已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值

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已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]

已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值
已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值

已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值
由题知X=1+Y,带入可得[(1+3Y)^2+(2+3Y)(1-3Y)-3(1+2Y)]/Y=-3Y/Y=-3

既然所求式子的值是独立于x,y而存在的,
说明它的值与x,y无关,随便取x=0,y=-1即可,代入式子求得式子的值是
-3

乘出来化简一下,括号里是3y^2-3xy,然后再除以y,得到3(y-x),代入为-3啦。。。哈