Use Gaussian elimination to find all solutions for the linear systems represented by each of the following augmented coefficient matrices, if one exists. If no solution exists, explain how you

know that. \text { 14. }\left[\begin{array}{ccccc} 0 & 1 & 2 & -4 & -9 \\ 2 & -1 & 0 & 1 & 6 \\ 1 & 1 & 1 & 1 & 14 \\ 0 & 0 & -1 & 1 & 1 \end{array}\right]