Finding Number of ways using Permutation and Combination

"1. At a college library exhibition of faculty publications, four mathematics books, four social science books, and four biology books will be displayed on a shelf. (a) In how many ways can the twelve books be arranged on the shelf? (b) In how many ways can the twelve books be arranged on the shelf if books on the same subject matter are placed together? 2. In how many different ways can a panel of 12 jurors and 2 alternates be chosen from a group of 17 prospective jurors? "