If 2 math books, 3 english books, and 4 history books are to be arranged on a book shelf. How many arrangements are possible if (a) books of the same subject have to be next to each other; (b) only...

If 2 math books, 3 english books, and 4 history books are to be arranged on a book shelf. How many
arrangements are possible if
(a) books of the same subject have to be next to each other;
(b) only the math books have to be next to each other;
(c) there has to be a math book at each end.