1. The problem statement, all variables and given/known data x1 + 2x2 = 9 , 6x1 + 6x2 -8x3 = 1 , -3x2 +x3 = 0 Here's a question from my book . I'm asked to find the x1 , x2 and x3 by using the gaussian elimination with pivoting . 2. Relevant equations 3. The attempt at a solution Pls refer to this thread for the lecturer's method https://www.physicsforums.com/threads/gaussian-elimination-pivoting.905132/#post-5699372 By using the lecturer's method ( circle out the max element in each column ) , I found that all the greatest element lies in 6x1+ 6x2 - 8x3 = 1 ... So , how could all the largest element lies in the same row ?