问题 解答题
计算:
(1)
1
9x2
+
5
6x
-
3
4x2

(2)a+2-
4
2-a

(3)
x2-4y2
x2+2xy+y2
÷
x+2y
x2+xy

(4)1-
a-b
a+2b
÷
a2-b2
a2+4ab+4b2
答案

(1)原式=

4+30x-27
36x2

=

30x-23
36x2

(2)原式=

a2-4+4
(a-2)

=

a2
a-2

(3)原式=

(x+2y)(x-2y)
(x+y)2
×
x(x+y)
x+2y

=

x2-2xy
x+y

故答案为

30x-23
36x2
a2
a-2
x2-2xy
x+y

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