题目内容
(2012•德阳)计算:
+
=
| x2 |
| x-5 |
| 25 |
| 5-x |
x+5
x+5
.分析:公分母为x-5,将分母化为同分母,再将分子因式分解,约分.
解答:解:
+
=
-
=
=
=x+5,
故答案为:x+5.
| x2 |
| x-5 |
| 25 |
| 5-x |
| x2 |
| x-5 |
| 25 |
| x-5 |
=
| x2-25 |
| x-5 |
=
| (x+5)(x-5) |
| x-5 |
=x+5,
故答案为:x+5.
点评:本题考查了分式的加减运算.分式的加减运算中,如果是同分母分式,那么分母不变,把分子直接相加减即可;如果是异分母分式,则必须先通分,把异分母分式化为同分母分式,然后再相加减.
练习册系列答案
相关题目