$\begin{gathered}
  \left\{ \begin{gathered}
  2x - 4y = 10 \hfill \\
  x + 8y =  - 15 \hfill \\ 
\end{gathered}  \right.\begin{array}{*{20}{c}}
  {\xrightarrow{{ \times 2}}} \\ 
  {} 
\end{array}\underline {\left\{ \begin{gathered}
  4x - \cancel{{8y}} = 20 \hfill \\
  x + \cancel{{8y}} =  - 15 \hfill \\ 
\end{gathered}  \right.}  \hfill \\
  \,\,\,\,\,1 + 8y =  - 15\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,5x = 5 \hfill \\
  \,\,\,\,\,\,\,\,\,\,\,8y =  - 15 - 1 =  - 16\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x = \frac{5}{5} \hfill \\
  \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,y = \frac{{ - 16}}{8}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\boxed{x = 1} \hfill \\
  \,\,\,\,\,\,\,\,\,\boxed{y =  - 2} \hfill \\ 
\end{gathered} $