In Exercises 11-16: a) Find a matrix B in reduced echelon form such that B is row equivalent to the given matrix A. b) Find a basis for the null space of A. d) Exhibit a basis for the row space of A. 1 2 3-1 11. A= 3 5 8-2 1 1 2 0 1 12 12. A = 1 12 2 3 5 1 2 1 0 2 5 3-1 13. A= 20 2 0 2 0 1 1 -1 2 20 14. A = 2 1 1 2 30 1 21 15. A= 2 4 1 3 62 16.A= 21 2 221 230