题目内容
化简:
(1)(a-2)•
(2)
+
.
(1)(a-2)•
| a2-4 |
| a2-4a+4 |
(2)
| a-b |
| a+2b |
| a2-b2 |
| a2+4ab+4b2 |
考点:分式的混合运算
专题:
分析:(1)把分式的分子和分母分解因式,然后进行乘法运算;
(2)首先把分式进行通分,然后进行化简即可.
(2)首先把分式进行通分,然后进行化简即可.
解答:解:(1)原式=(a-2)•
=a+2;
(2)原式=
+
=
+
=
=
.
| (a+2)(a-2) |
| (a-2)2 |
=a+2;
(2)原式=
| a-b |
| a+2b |
| (a+b)(a-b) |
| (a+2b)2 |
=
| (a-b)(a+2b) |
| (a+2b)2 |
| (a+b)(a-b) |
| (a+2b)2 |
=
| (a-b)(a+2b+a+b) |
| (a+2b)2 |
=
| (a-b)(2a+3b) |
| (a+2b)2 |
点评:本题主要考查分式的混合运算,通分、因式分解和约分是解答的关键.
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