4.7 Find the determinant of each of the following matrices 2 aa+2 -4 0 0 c.0 4 0 3 -7 2 a.3 b b+3 |. 43-1710 4.8 Let A, B,C be 6 x 6 matrices such that det (A)-3, det(B)- 2, and det(C)0. Compute a. det(A-1) b. det (3A) c. det(A2BT) d. det(ABA-) e. det(A), where -rref(A) 4.9 Show that if A0, then the matrix A cannot be invertible