\begin{cases}

 & \text \\ \sqrt{9{x}_{1}^{2}+18{x}_{2}^{2}+9,99{x}_{1}{x}_{2}}\rightarrow min& 
& \text  \\ 2{x}_{0}+6{x}_{1}+8{x}_{2}\geq 7 &
& \text\\  {x}_{0}+{x}_{1}+{x}_{2}=1&

\end{cases}