问题:
计算:
(1)
a
a-b
+
b
b-a
(2)
1
x+2
-
x2+2x+1
x+2
÷
x2-1
x-1
.
计算:
(1)
+
(2)
-
÷
.
(1)
a |
a-b |
b |
b-a |
(2)
1 |
x+2 |
x2+2x+1 |
x+2 |
x2-1 |
x-1 |
参考答案: