1) What can you say about the shape of an m x n matrix A when the columns of A form a basis of R^m? 2) Find the determinant by row reduction to echelon form. det 1 3 3 -4 0 1 2 -5 2 5 4 -3 -3 -7 -5 -2 3) Combine the methods of row reduction and cofactor expansion to compute the determinant det -1 2 3 0 5 4 6 6 3 4 3 0 4 2 4 3 4) Let A and P be n x n matrices, with P invertible. Show that det(PAP^-1) = det A Solution Q#3 ANS.