当x−yx+y=2时,代数式x−yx+y-2x+2y/x−y的值是_.

问题描述:

x−y
x+y
=2时,代数式
x−y
x+y
-
2x+2y
x−y
的值是______.

x−y
x+y
=2,∴x-y=2(x+y),
x−y
x+y
-
2x+2y
x−y
=
2(x+y)
x+y
-
2(x+y)
2(x+y)
=2-1=1,
故答案为:1.