Show that each of the arguments in Exercises 1 and 2 is valid by using a direct proof or by using an indirect proof.

1. If Marissa does not go to the movies, then she is not idle. If Marissa is not in a knitting class, she is idle. Marissa is not in a knitting class. Therefore, Marissa goes to the movies.

2. Sydney collects a penalty payment if Norman leaves a mess in the apartment. Rachel cleans the apartment or Norman leaves a mess in the apartment. Rachel does not clean the apartment. Prove that Sydney collects a penalty payment?