Thread: Gruop Axioms

I have a problem.

I know there is an identity to this group but not sure how to prove it.

(Q*,o), where x o y = xy/7

Can anyone help?

Thanks

We require e * a = a.
In other words,
e * a = ea/7 = a
Since we're now in "regular" rational multiplication, cancel the a's.
e/7 = 1
e = 7.

Check.

Thanks for your help.