\[7x^{2} \leq 3x\]
\[7x^{2} = 3x\]
\[7x^{2} - 3x = 0\]
\[x(7x - 3) = 0\]
\[x = 0,\ \ \ x = \frac{3}{7}\]
\[Ответ:\ \ x \in \left\lbrack 0;\frac{3}{7} \right\rbrack.\]