For the first one, consider that (n-1)! contains any integer inferior or equal to n-1 as a factor, that is to say any integer inferior to n. Now, if n is a composite number, then it's the product of at least 2 integers that are inferior to n. But these 2 numbers are in the product (n-1)!. Thus you can retrieve n in (n-1)! --> n divides (n-1)!
I hope it's clear enough... !