\(\displaystyle \\
\begin{cases}
x+y = 54 \\
x-5y = 0~~~~~| \cdot (-1)
\end{cases} \\ \\ \\
\begin{cases}
x+y = 54 \\
-x+5y = 0
\end{cases} \\
\texttt{-------------- gather equations} \\
.~~/~~~~~6y = 54 \\ \\
y = \frac{54}{6} = \boxed{9} \\ \\
x = 54 - y = 54 - 9 = \boxed{45} \\ \\
\texttt{Problem solution: } \boxed{x = 45 ~~ and ~~ y = 9 }\)
