Решите уравнение: (2x-3)(x+1)+(x-6)(x+6)+x=0.

\[3x^{2} - 39 = 0\]

\[3 \cdot \left( x^{2} - 13 \right) = 0\]

\[3 \cdot \left( x - \sqrt{13} \right)\left( x + \sqrt{13} \right) = 0\]

\[x - \sqrt{13} = 0\ \ \ \ \ \ \ \ \ x + \sqrt{13} = 0\]

\[x = \sqrt{13}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x = - \sqrt{13}\]

\[Ответ:x = \sqrt{13};\ x = - \sqrt{13}.\]