a) There are 12 letters, and if these were all unique, there would be 12! unique ways to arrange them. However, we must divide out the duplicate (non-distinct) arrangements. For this, we note there are 2 A's, 2 R's, 2 N's, and 2 E's, each of which contributes 2! non-distinct arrangements:
Number of unique arrangements = = 29937600
Part (b) can be done similarly. Since the arrangements begin with EE, that effectively leaves 10 letters to arrange, and you'll need to remove duplicates in a similar way as in part (a). It is as if the E's are removed and you repeat part (a) without the E's.
Hint: the answer will be 10! / (something)