-- Sep 6 In-Class Exercise Thread

Matrix in upper triangular form is: [1 2 3] [4 5 6] [7 8 9] 3 x r1 + r2 1,2,3 7,11,15 7,8,9 r3-r2 1,2,3 7,11,15 0,-3,-6 r2 = -7*r1+r2 1,2,3 0,-3,-6 0,-3,-6 2 rows are identical hence det(A) = 0 (Reposted as the one I posted in class on Sep 6 did not go through due to Internet connection issue.