\[\boxed{\text{349\ (349).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[y\ :x = 5\ (ост.\ 10)\]
\[y = 5x + 10;\ \ где\ x > 10 \Longrightarrow\]
\[\Longrightarrow область\ определения\ \]
\[(10; + \infty).\]
\[При\ x = 15:\]
\[y = 5 \cdot 15 + 10 = 85.\]
\[При\ x = 50:\]
\[y = 5 \cdot 50 + 10 = 260.\]
\[Ответ:y = 5x + 10;\ \ (15;85);\ \ \]
\[(50;260).\]