We have E_{a,b}(x)=(a.x+b)(mod 26). Find a,b if you know 2 values E_{a,b}(x)
E_{a,b}(3)=5, E_{a,b}(6)=7
=>(3a+b)%26=5
(6a+b)%26=7
I don't know how to solve these equations, so I can't find a,b
Please, help me or give me some ideas to solve it. Thank you very much!