Exercise III (10 + 5= 15 points) 1. Use elimination (and permutation when needed) matrices to put the following matrix in upper triangular form. At each step, determine which elimination (or permutation) matrix you used. a a a a a b b A = a b C C a b C 2. Find A's LU factorization. You should be able to conclude this quickly from part 1. What are the conditions on a, b, c, d to get A = LU with four pivots