Who or Whom?

Use who when you are referring to the subject of a sentence and whom when you are referring to the object (who is receiving the action).

Examples:
Who wrote that article? Who can be replace by a subject/noun and rewritten as a sentence or the answer to the question: Chris Lang wrote that article.

Who is coming to the meeting? Rewrite: Thomas, Linda, Dana, and Brad are coming to the meeting.

Whom did you invite to dinner? Rewrite: I invited Brooke and Kristin to dinner.

Whom do you live with? Rewrite: I live with my mother and my brother.