"Where are the restroom?" or "Can you tell me where the restroom is?" are similar requests for directions. are correct, but the first one sounds less polite. It is not enough to just ask a question (correct). We also need to learn how to be polite when we ask help. Polite questions are usually longer and sometimes they sound like a kind of request. It seems more difficult to speak (polite), but it is very important (learn) how to use the right language in different situations.