问题 选择题
已知集合A={x|
6
5-x
∈N*,且x∈Z},则A=(  )
A.{2,3}B.{1,2,3,4}C.{1,2,3,6}D.{-1,2,3,4}
答案

∵集合A={x|

6
5-x
∈N*,且x∈Z},

∴5-x>0可得x<5,

取x=4,

6
5-4
=6,满足;

取x=3,

6
5-3
=3,满足题意;

取x=2,

6
5-2
=2,满足题意;

取x=1,

6
4
=
3
2
,不满足题意,

取x=0,可得

6
5
,不满足题意;

取x=-1,可得

6
6
=1,满足题意;

取x=-2,可得

6
6-(-1)
=
6
7
,不满足题意;

若x<-2,可得

6
5-x
<1,不满足题意,

∴A={-1,2,3,4};

故选D;

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