\[3x^{2} - x(3x - 4) = 8\]
\[3x^{2} - 3x^{2} + 4x = 8\]
\[4x = 8\]
\[x = 2\]
\[3x^{2} - x(3x + 4) = 8\]
\[3x^{2} - 3x^{2} - 4x = 8\]
\[- 4x = 8\]
\[x = - 2.\]
\[x_{2} = - 2 \Longrightarrow \text{\ \ \ \ }\]
\[\Longrightarrow \ y_{2} = 3 \bullet ( - 2) + 4 =\]
\[= - 6 + 4 = - 2.\]
\[Ответ:(2;2),\ ( - 2;\ - 2).\]