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='32670' and id < 2598783 and id<>'2598783' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='32670' and id > 2598783 and id<>'2598783' order by id asc limit 5