When you are asking about a location someone is coming from you need to use the preposition “from” with “where”: “Where are you coming from?” But when you are discussing a destination instead of a point of departure, don’t add a preposition. It’s not “Where are you going to?” but “Where are you going?”
Similarly, when asking about the location of a place, “at” should not be used after “where.” It’s not “Where is the movie theater at?” but “Where is the movie theater?”
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