问题 解答题
计算下列各题:
(1)
2a
a+b
÷
2ab
a2-b2
(2)
2x
x2-4y2
-
1
x-2y
答案

(1)原式=

2a
a+b
(a+b)(a-b)
2ab

=

a-b
b

(2)原式=

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

=

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

=

x-2y
(x+2y)(x-2y)
            

=

1
x+2y

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