\[- x\left( \frac{1}{3} - x \right) = (x - 1)(x + 1)\]
\[- \frac{1}{3}\ x + x^{2} = x^{2} - 1\]
\[- \frac{1}{3}x = - 1\]
\[x = 3\]
\[Ответ:x = 3.\]