题目内容
计算:(1)
| x2 |
| y-x |
| y2 |
| y-x |
| a2-4 |
| a2-4a+4 |
| 2-a |
| a+2 |
| a |
| a-2 |
分析:(1)直接通分,分子因式分解,约分;
(2)将括号里的分式因式分解,约分,通分,再将除法化为乘法进行运算.
(2)将括号里的分式因式分解,约分,通分,再将除法化为乘法进行运算.
解答:解:(1)原式=
=-
=-x-y;
(2)原式=[
-
]•
=
•
=
•
=
.
| x2-y2 |
| y-x |
| (x+y)(x-y) |
| x-y |
(2)原式=[
| (a+2)(a-2) |
| (a-2)2 |
| a-2 |
| a+2 |
| a-2 |
| a |
=
| (a+2)2-(a-2)2 |
| (a-2)(a+2) |
| a-2 |
| a |
=
| 8a |
| (a-2)(a+2) |
| a-2 |
| a |
| 8 |
| a+2 |
点评:本题考查了分式的混合运算.关键是明确混合运算的顺序,将分式通分,因式分解,约分,有括号的先算括号.
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