对称Y形和对称形网络等效变换的公式为。（   ）

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69506' and id < 4502718 and id<>'4502718' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69506' and id > 4502718 and id<>'4502718' order by id asc limit 5