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!