问题
解答题
先化简:
|
答案
原式=
×(x+y)(x-y) xy
+1 x+y
-(x+y)2 xy(x+y)
(3分)(x-y)2 xy(x-y)
=
+x-y xy
-x+y xy x-y xy
=
;(5分)x+y xy
∵x=
+1,y=2
-1,2
∴x+y=2
,xy=1(6分)2
∴原式=2
.(7分)2
故答案为2
.2
先化简:
|
原式=
×(x+y)(x-y) xy
+1 x+y
-(x+y)2 xy(x+y)
(3分)(x-y)2 xy(x-y)
=
+x-y xy
-x+y xy x-y xy
=
;(5分)x+y xy
∵x=
+1,y=2
-1,2
∴x+y=2
,xy=1(6分)2
∴原式=2
.(7分)2
故答案为2
.2