In each part, find a basis for the given subspace of R³, and state its dimension. a. The plane 3x - 2y + 5z = 0. b. The plane x - y = 0. c. The line x = 2t, y = -t, z = 4t. d. All vectors of the form (a, b, c), where b = a + c. 9. Find the a. The vector space of all diagonal n x n matrices. b. The vector space of all symmetric nx n matrices. c. The vector space of all upper triangular n x n matrices. dimension of each of the following vector spaces.