Problem 3 (10 marks) O points possible (ungraded) Let's consider a linear system Ax = b. Where, A = 1 2 4 4 12 20 20 60 2 And, B = 0 1 2 (a) Write down all the linear equations that they represent. (1 Mark) (b) Use Gaussian elimination to turn it into an upper triangular form. (3 Marks) c) Construct the lower triangular matrix L. (1 Mark) (d) Solve the system from the LU decomposed form