(G;x) is a group ( e it's identity element). and are a subgroups from (G,x).

={ / } x }

1)-I must show that : is a subgroup from(G;x)

2)- We assume that and are finished and ={e} and:

: x

( ; )

I must show that is surjective and Card( )=Card( )Card( )

I don't know anything!!!!!!! Can you give me some help please????