If G is a group and [G:Z(G)]=4, prove that G/Z(G) isomorphic to Z2+Z2. Should I look at the cosets formed by G/Z(G) or what? I hve no clue, need help
P.S. If you aren't sure why those are the only two groups you need merely note that any group of order where is a prime is abelian and the rest follows from the fundamental theorem of finitely generated abelian groups.