问题 解答题
计算
(1)
2x
x2-4
-
1
x-2

(2)
a
a-1
÷
a2-a
a2-1
-
1
a-1
答案

(1)原式=

2x
(x+2)(x-2)
-
x+2
(x+2)(x-2)

=

2x-x-2
(x+2)(x-2)

=

1
x+2

(2)原式=

a
a-1
×
a+1
a
-
1
a-1

=

a+1
a-1
-
1
a-1

=

a
a-1

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