1 Exercise 5.1.3 In each case determine if the given vec- tors span R4. Support your answer. a. {(1, 1, 1, 1), (0, 1, 1, 1), (0, 0, 1, 1), (0, 0, 0, 1)}. b. {(1, 3, 5, 0), (-2, 1, 0, 0), (0, 2, 1, −1), (1, 4, 5, 0)}. } d. If x is in U and U span {x, y, z}. = span {y, z}, then U = e. The empty set of vectors in R" is a subspace of Rn 0 1 2 f. r 1 is in span , 0 0