\[y = 3x\]
\[3x = \sqrt{x}\]
\[9x^{2} = x\]
\[9x^{2} - x = 0\]
\[x(9x - 1) = 0\]
\[x = 0\ и\ x = \frac{1}{9}\]
\[\Longrightarrow пересекает\ в\ точках\ \]
\[\left( \frac{1}{9};\frac{1}{3} \right)\ и\ (0;0).\]