Row Reduction & Rank · Hard problem

For which value of $k$ is the system $A\mathbf x = \mathbf b$ with $A = \begin{pmatrix}1 & 4\\0 & 2\\-2 & -3\end{pmatrix}$ and $\mathbf b = \begin{pmatrix}14\\6\\k\end{pmatrix}$ consistent?