问题:
a+2
a2-4
=
1
( )
;
-x-y
-x+y
=
x+y
( )
,括号中应依次填上:______,______.
a+2 |
a2-4 |
1 |
( ) |
-x-y |
-x+y |
x+y |
( ) |
参考答案: