1. The problem statement, all variables and given/known data Given this matrix: I am asked to find values of the coefficient of the second value of the third row that would make it impossible to proceed and make elimination break down. 2. Relevant equations Gaussian elimination methods I used given here: http://mathworld.wolfram.com/GaussianElimination.html 3. The attempt at a solution I managed to write the original matrix in its reduced echelon form; however I'm having trouble finding the value that would make elimination impossible, even when interchanging rows. I've tried zero, but that didn't help me at all.