题目内容
先化简
，再从?2，0，1，2中选择一个合适的数代入，求出这个代数式的值．
-1解析:
解：原式=
················ 2’
=
····················· 3’
=
·························· 4’
=
···························· 5’
取x=1代入得，原式=?1
解：原式=
················ 2’=
····················· 3’=
·························· 4’=
···························· 5’取x=1代入得，原式=?1
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