help with 1,2 and 3

1. Show that E; is not isomorphic to I: by showing that the rst group has an element of order 4 but the second group does not. {5) 2. If [111' is a left coset of H in G and :11 E aH. show that the left coset of H generated by 1:11 is also all. (5} 3. Let G 2 ER and let N be the cyclic subgroup generated by the congruence class of 3. Find the three elements of G/N, found by adding [1]\" and [2]\" to each element of N. [6}