Placing an "adjective" before a verb, as in "resmi dibuka", was previously taught as a way to turn an adjective into an adverb in earlier lessons. "Resmi dibuka" also seems to be widely used in news headlines. Why is it not accepted?
Is secara the same as dengan?
Yes. Both "secara" and "dengan" can be used to form adverbial phrase.
Sekolah ini resmi dibuka.
This alternate answer is ALSO CORRECT.
I am an Indonesian native speaker and I know that that sentence is CORRECT.