Đáp án:
Giải thích các bước giải:
\(\begin{array}{l}
a. \Leftrightarrow \left\{ \begin{array}{l}
m - 2 = 0\\
{n^2} - 4n + m \ne 0
\end{array} \right. \to \left\{ \begin{array}{l}
m = 2\\
{n^2} - 4n + 2 \ne 0
\end{array} \right.\\
\to \left\{ \begin{array}{l}
m = 2\\
\left[ \begin{array}{l}
n \ne 2 + \sqrt 2 \\
n \ne 2 - \sqrt 2
\end{array} \right.
\end{array} \right.\\
b.\left( {{m^2} - 1} \right){x^3} + \left( {{m^2} - 4m + 3} \right){x^2} - 3x + 2 = 0\\
\to \left\{ \begin{array}{l}
{m^2} - 1 = 0\\
{m^2} - 4m + 3 \ne 0
\end{array} \right. \to \left\{ \begin{array}{l}
m = \pm 1\\
\left[ \begin{array}{l}
m \ne 3\\
m \ne 1
\end{array} \right.
\end{array} \right.\\
\to m = - 1
\end{array}\)
