已知2x-y=10,求[(x²+y²)-(x-y)²+2y(x-y)]/4y的值我是这样做的,老师说不对：[(x²+y²)-(x-y)²+2y(x-y)]/4y=（x²+y²-x²+2xy-y²+2xy-2y²）/4y=（4xy-2y²）/4y=[2y（2x-y）]/4y=二分

已知2x-y=10,求[(x²+y²)-(x-y)²+2y(x-y)]/4y的值我是这样做的,老师说不对：[(x²+y²)-(x-y)²+2y(x-y)]/4y=（x²+y²-x²+2xy-y²+2xy-2y²）/4y=（4xy-2y²）/4y=[2y（2x-y）]/4y=二分
已知2x-y=10,求[(x²+y²)-(x-y)²+2y(x-y)]/4y的值
我是这样做的,老师说不对：[(x²+y²)-(x-y)²+2y(x-y)]/4y=（x²+y²-x²+2xy-y²+2xy-2y²）/4y=（4xy-2y²）/4y=[2y（2x-y）]/4y=二分之一（2x-y)=二分之一乘10=5

已知2x-y=10,求[(x²+y²)-(x-y)²+2y(x-y)]/4y的值我是这样做的,老师说不对：[(x²+y²)-(x-y)²+2y(x-y)]/4y=（x²+y²-x²+2xy-y²+2xy-2y²）/4y=（4xy-2y²）/4y=[2y（2x-y）]/4y=二分
[(x²+y²)-(x-y)²+2y(x-y)]/4y=（x²+y²-x²+2xy-y²+2xy-2y²）/4y
=（4xy-2y²）/4y
=[2y（2x-y）]/4y
=（2x-y)/2
=10/2
=5
对的,可能你的老师同你的做法在步骤上存在不同,但不应该说你是错的.