36) Prove that if G/Z (G) is cyclic then G is abelian. [If G/Z (G) is cyclic with generator xZ (G), show that every element of G can be written in the form x"z for some integer a E Z and some element...

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Extracted text: 36) Prove that if G/Z (G) is cyclic then G is abelian. [If G/Z (G) is cyclic with generator xZ (G), show that every element of G can be written in the form x"z for some integer a E Z and some element z E Z(G).]