Answer:
1. Whom was met by you?
2. To whom was the book given by you? OR Whom was the book given to by you?
3. By who were you called a list?
Explanation:
1. This is more simple. You simply find the verb "meet", determine the tense using the auxiliary verb "did" (past tense); from this you get "met". Then identify the subject ("you"), and string it all together with the passive voice form of questions: object + verb + by + subject, or "Whom was met by you?".
2. For this question, the original active voice question was grammatically wrong: it should be "To whom did you give the book?" or "Whom did you give the book to?" Using the same method mentioned in question 1, you'll get the answer.
3. This is a little different from the other two questions, since it's asking about the identity of the subject, not the object. This means the sentence structure should be similar, but with the subject moved to the start. This could technically be done to all of the questions, but most people use the "object + verb to be + verb + by + subject" form for finding the object.
Anyways, back to the question: the form used should be "by + subject + verb to be + object + verb". This explains the answer.
Sorry if I didn't explain the answers that well
