问题 解答题
(1)x-
x2-y2
x
+
x2+y2
x
-y;
(2)
2x-1y-1(x+y)
x-1+y-1
答案

(1)原式=(x-y)-(

x2-y2
x
-
x2+y2
x

=(x-y)-

-2y2
x

=

x-y
x
-
-2y2
x

=

x2-xy+2y2
x

(2)原式=

2(x+y)
xy
1
x
+
1
y

=

2(x+y)
xy
y+x
xy

=

2(x+y)
xy
xy
x+y

=2.

故答案为

x2-xy+2y2
x
、2.

选择题
问答题 简答题