计算（1）|-2|-9+(π-3)°（2）(1+x-2x+2)÷2xx2-4_爱下问搜题

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问题解答题

计算
（1）|-2|-

9

+(π-3)°
（2）(1+

x-2

x+2

)÷

2x

x2-4

答案

（1）原式=2-3+1=0；

（2）原式=

2x

x+2

×

(x+2)(x-2)

2x

=x-2．

选择题

You can hardly imagine the difficulty she had ________ enough evidence to prove the case.[ ]

A. collected

B. to collect

C. collecting

D. have collected

问答题简答题

简述管线的修复方法。