1. (10 points) True/False questions. No justification necessary. (a) True False The matrix 010 0 01 10 0 0 0 010 0 0 0 01 0 0 0 0 0 is in reduced row-echelon form. (b) True False If A is a 2 x 3 matrix, B is a 3 x 4 matrix, and C a 4 x 5 matrix, then ABC is a 2 x 5 matrix. (c) True False The determinant of an invertible matrix can be zero. (d) True False The determinant of a matrix that has two identical rows is zero. (e) True False The determinant of a diagonal matrix is zero if one of its diagonal entries is zero. (f) True False If v1, . ...Vn are vectors in a vector space V, then the span of V1, . . . , Un is a subspace of V. (g) True False The set of row vectors W = { [a 6 1] : a, beR}, is a subspace of M1x3(IR). (h) True False The vector x3 -1 is in the span of the vectors x2-1, 3, and x2+x-1. (i) True False Suppose A and B are 3 x 3 matrices. If rref(A) and rref ( B) both have one leading 1, then rref (A + B) has two leading 1's. (j) True False A homogeneous linear system with 4 equations and 6 variables always has nontrivial solutions