\[3x^{2} - 8x - 4x + 16 - 4 = 0\]
\[3x^{2} - 12x + 12 = 0\ \ \ \ \ |\ :3\]
\[x^{2} - 4x + 4 = 0\]
\[(x - 2)^{2} = 0\]
\[x = 2.\]
\[Ответ:x = 2.\]