赞 suxingui0205 幼苗
共回答了20个问题采纳率：90% 举报
(x-y)²+(x+y)(y-x)-2x(1-y)
=(x²-2xy+y²)+(y²-2x²)-(2x-2xy)
=x²-2xy+y²+y²-2x²-2x+2xy
=-x²+2y²-2x
=-1²+2×(-2)²-2×1
=-1+8-2
=5
=(x²-2xy+y²)+(y²-2x²)-(2x-2xy)
=x²-2xy+y²+y²-2x²-2x+2xy
=-x²+2y²-2x
=-1²+2×(-2)²-2×1
=-1+8-2
=5
1年前 追问
1
明显不对啊 (x-y)²+(x+y)(y-x)-2x(1-y) =(x²-2xy+y²)+(y²-x²)-(2x-2xy) =x²-2xy+y²+y²-x²-2x+2xy =2y²-2x =2×(-2)²-2×1 =8-2 =6
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