\[6 \cdot \left( x^{2} - 4 \right) - 4x \cdot (x + 3) =\]
\[= 2x^{2} - 12x - 12\]
\[0x = - 12 + 24\]
\[0x = 12\]
\[Ответ:нет\ корней.\ \]