When A is invertible, MATLAB finds A 1 by factoring LU (where L may be permuted lower triangular), inverting L and U, and then computing U 1L-1. Use this method to compute the inverse of the given matrix A. 3-9 3 1 0 0 3 - -9 3 A = -12 33-6 where A = -4 1 0 ' 0 -3 6 0-3 3 0 1 1 0 0 -3 Compute U1 and L-1. U-1 = L-1 = Compute A-1 A-1 =