题目内容
化简求值:(
+
)÷
,其中x=2007.
| x |
| x-2 |
| x |
| x+2 |
| 4x |
| x-2 |
分析:先根据分式混合运算的法则吧原式进行化简,再把x的值代入进行计算即可.
解答:解:原式=[
+
]•
=
•
=
•
=
.
当x=2007时,原式=
=
.
| x(x+2) |
| (x-2)(x+2) |
| x(x-2) |
| (x-2)(x+2) |
| x-2 |
| 4x |
=
| x2+2x+x2-2x |
| (x-2)(x+2) |
| x-2 |
| 4x |
=
| 2x2 |
| (x-2)(x+2) |
| x-2 |
| 4x |
=
| x |
| 2(x+2) |
当x=2007时,原式=
| 2007 |
| 2×(2007+2) |
| 2007 |
| 4018 |
点评:本题考查的是分式的混合运算,熟知分式混合运算的法则是解答此题的关键.
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