Earnest has 8 different textbooks for his course this term that he wants to arrange along a single shelf. Two of the textbooks are for math, three are for CSC, two are for English, and one is for physics. how mamy ways can ernest arrangew the texbooks if: a) all the textbooks on the same subject must be positioned next to each other? b) in addition to the restriction in a) Earnest wants his math textbooks to be kept away from his CSC textbooks?