urgent hw trees-discrete maths!

1)a)how many nonisomorphic unrooted trees are there aith 4vertices?

b)how many noniomorphic rooted trees are there with 4vertices?(using iomorphism for directed graphs)

2)either draw a full m-ary tree with 76 leaves and height 3 where m is a positive integer or show that no such tree exists?

3)a full m-ary tree T has 81 leaves and height 4.

a)give the upper and lower bounds for m.

b)what is m if T is also balanced?

a complete m-ary tree is a full m-ary tree where every leaf is at the same level.