Enter the matrix a and the vector b in matlab: a = [4 1 2 −3; −3 3 −1 4; −1 2 5 1; 5 4 3 −1] , b = [−16; 20; −4; −10]the exact solution to the system ax = b is the vector x = (−1, 1, −2, 3)^t .(a) enter [l, u,p] = lu(a) to find the lu decomposition of the matrix p a (don’t forget that you will need p*b). verify that p a = lu.(b) use the lu decomposition you found in part (a) to solve the system ax = b. call the computed solution x_lu.(c) enter the vector x and compare your solution x lu from part (b) with the exact solution x by computing norm(x_lu - x)