9. Let A be a 4 x 5 matrix and let U be the reduced row echelon form of A. Given that the first two columns of A are 2 1 2 C1 = , 02 = -3 3 2 and 1020 -1 0130 -2 U = 0 0 01 5 0 0 0 0 0 (a) Find a basis for N(A)(b) Given that x0 is a solution to Ax = b._ where 3 0 5 2 1'): XD I 0 3 2 4 0 nd all solutions to the system and determine the remaining column vectors of A