\[Уравнение\ имеет\ \]
\[единственный\ корень\ \]
\[при\ D = 0.\]
\[(m - 2)x² - (2m - 4)x + 12 = 0\]
\[m - 2 = 0 \Longrightarrow m = 2.\]
\[= 4m^{2} - 64m + 112 =\]
\[= 4 \cdot \left( m^{2} - 16m + 28 \right)\]
\[4 \cdot \left( m^{2} - 16m + 28 \right) = 0\]
\[m^{2} - 16m + 28 = 0\]
\[D = ( - 16)^{2} - 4 \cdot 1 \cdot 28 =\]
\[= 256 - 112 = 144\]
\[m_{1} = \frac{16 + \sqrt{144}}{2} = \frac{16 + 12}{2} =\]
\[= \frac{28}{2} = 14\]
\[m_{2} = \frac{16 - \sqrt{144}}{2} = \frac{16 - 12}{2} =\]
\[= \frac{4}{2} = 2\]
\[Ответ:при\ m = 14;m = 2.\]