问题 解答题
计算:
(1)
3a
3a-2b
-
2b
3a-2b
=______;
(2)
a+2b
a-b
+
b
b-a
-
2a
a-b
=______;
(3)
x
(x-1)2
-
1
(x-1)2
=______;
(4)
x2-1
x2+2x+1
+
2
x+1
=______.
答案

(1)原式=

3a-2b
3a-2b
=1;

(2)原式=

a+2b-b-2a
a-b
=
-(a-b)
a-b
=-1;

(3)原式=

x-1
(x-1)2
=
1
x-1

(4)原式=

(x+1)(x-1)
(x+1)2
+
2
x+1
=
x-1+2
x+1
=
x+1
x+1
=1.

故答案为:(1)1;(2)-1;(3)

1
x-1
;(4)1

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