2bc-3ac+2ab-(ab-2bc+3ac)
=2bc-3ab+2ab-ab+2bc-3ac
=4bc-6ac+ab
所以 某整式就是4bc-6ac+ab
所以 正确结果为 4bc-6ac+ab-(ab-2bc+3ac)
=4bc-6ac+ab-ab+2bc-3ac
=6bc-9ac
2bc-3ac+2ab-(ab-2bc+3ac)
=2bc-3ab+2ab-ab+2bc-3ac
=4bc-6ac+ab
所以 某整式就是4bc-6ac+ab
所以 正确结果为 4bc-6ac+ab-(ab-2bc+3ac)
=4bc-6ac+ab-ab+2bc-3ac
=6bc-9ac