Q2. For given state space model [10 4 0 A = 9 0 10 -4 0 -4] B=0 C=[56 0], D = [3] a) Investigate the controllability using PBH eigenvector test and, if there exists, find the uncontrollable modes. b) Investigate the observability using PBH rank test and, if there exists, find the unobservable modes. c) Is your state space model minimal, why? If not, find its minimal state space representation. d) Check your results with MATLAB, etc.