(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.
