问题 解答题
若x,y为实数,且满足(x-2)2+
y-3
=0
,试求
x2-2xy+y2
x2-y2
的值.
答案

∵(x-2)2+

y-3
=0,

∴x-2=0,y-3=0,即x=2,y=3,

x2-2xy+y2
x2-y2
=
(x-y)2
(x+y)(x-y)
=
x-y
x+y
=
2-3
2+3
=-
1
5

单项选择题
问答题 简答题