因为:某整式+(ab-2bc+3ac)=(2bc-3ac+2ab)
所以:
某整式=(2bc-3ac+2ab)-(ab-2bc+3ac)=4bc-6ac+ab
正确结果=某整式-(ab-2bc+3ac)
=(4bc-6ac+ab)-(ab-2bc+3ac)
=6bc-9ac