For which value of k does the matrix A= |4 k| |-7 -5| have one real eigenvalue of multiplicity 2? 3. The attempt at a solution - I tried by setting this problem up with det(A-(lambda)I) and trying to solve like that, but I can't seem to get it that way either. I am getting (lambda)^2+(lambda)-20+7k=0, but I don't know what to do from there. Please help.