True or False In abelian group all subgroups are normal A su
     True or False  In abelian group all sub-groups are normal  A subgroup H of a group G is normal elementof iF only iF For every g elementof G gH = Hg 
  
  Solution
a) True
b)true
In abstract algebra a normal subgroup is a subgroup which is invariant under conjugation by members of the group of which it is a part.In other words a subgroup h of G if and only if hg=gh for all g in G

