如果实数x，y满足条件 ，那么z=x+2y的最大值为

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='32858' and id < 2619138 and id<>'2619138' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='32858' and id > 2619138 and id<>'2619138' order by id asc limit 5