Find a basis and calculate the dimension of the following subspaces of R4. (a) span{[l -1 2

Question:

Find a basis and calculate the dimension of the following subspaces of R4.
(a) span{[l -1 2 O], [2 3 0 3]T, [1 9 -6 6]T}.
(b) span{[2 1 0 -1]T, [-1 1 1 1]T, [2 7 4 5]T}.
(c) span{[-l 2 1 0]T, [2 0 3 -1]T, [4 4 11 -3]T,[3 -2 2 -1]T}.
(d) span{[-2 0 3 1]T, [1 2-1 0]T, [-2 8 5 3]T, [-1 2 2 1]T}.