5. Let 5 6 7 8 0 3 2 A = 0 0 0 1 0 0 -1 -2, (a) The matrix A can be decomposed using partial pivoting as PA=LU, where U is upper triangular, L is unit lower triangular, and P is a permutation matrix. Find the 4 x 4 matrices U, L, and P. (b) Given the right-hand-side vector b = (26,9,1,-3), find x that satisfies Ax = b. (Show your method: do not just guess.)