\[y = \frac{1}{5}x\]
\[y = - 3:\]
\[\ \frac{1}{5}x = - 3\]
\[x = - 15.\]
\[y = \frac{1}{5}:\ \ \]
\[\frac{1}{5}x = \frac{1}{5}\]
\[x = 1.\]
\[y = 2:\ \ \]
\[\frac{1}{5}x = 2\]
\[x = 10.\]
\[y = 0,4:\ \ \]
\[\frac{1}{5}x = 0,4\]
\[x = 2.\ \]