I am studying maths and have the following question set by my professor.
I thought the answer was 5, because: 3 . 5 = 15, and 15 mod 7 is 1. Since 1 mod 7 = 1 that means they match.
However, I looked at the formula and noticed both variables are z, which leads me to believe they both have to be 3. Look for the red in the picture. I guess my question is what the answer is, and why?