\[3x^{2} - 4x + 1 < 0\]
\[D_{1} = 4 - 3 = 1\]
\[x_{1} = \frac{2 + 1}{3} = 1;\]
\[x_{2} = \frac{2 - 1}{3} = \frac{1}{3};\]
\[\left( x - \frac{1}{3} \right)(x - 1) < 0\]
\[\frac{1}{3} < x < 1.\]
\[Ответ:\ \frac{1}{3} < x < 1.\]