Start Typing in MATLAB 9.2 Exercise 4 9 6 -3 Let AB = 6 0 8 1 12 6 5 18 33 11 9 -2 8 6 18 6 a.) (Enter AB in MATLAB.) Type: ABRF= rref(AB) Decide what is the rank of AB and what is nullity of AB, then enter them in the following format: RANKAB= your answer for rank(AB) NULLAB= your answer for null(AB) Recall that to show that a vector b in column space of a matrix AB you need to show that the linear system (AB)X = b is consistent. you may do this in one of the following way: . Show that rank(A) = rank([AB b]). . Finding rref(AB)