Question

6^-1 (mod 26)

Answer 1

Do you know how to do it without gcfs?

Answer 2

Note that \(\gcd(6, 26)=2\neq1\), so there is no inverse.

Answer 3

that was supposed to be a 7

Answer 4

Well, if you want to do it without gcf's or gcd's, the only way I know of that isn't guess and check, would be to somehow apply the Chinese Remainder Theorem.