اگر دو تابع $f(x)=\left\{ \begin{matrix}
\frac{2{{x}^{2}}-24x+72}{x-6}\,\,\,\,\,\,\,\,\,\,\,\,x\ne 6 \\
k\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x=6 \\
\end{matrix} \right.$ و $g(x)=ax-b$ با هم مساوی باشند، مقدار $a+x+k$ کدام است؟