I have tried to follow the previous posts and I'm still confused.
I can follow the Euclidean algorithm to find gcd and I know that gcd has to equal 1 for there to be an inverse, in other words a and m have to be relatively prime, but could someone lay out the steps? Let a=4 and m=9.
Then 9 = 2(4) + 1
and 4 = 4(1) + 0
so 1 = 9 - 2(4)
Then do you set 4p = 1 (mod 9) ?
I really don't understand how the process (algorithm) continues.