Đáp án: C
Giải thích các bước giải:
$\begin{array}{l}
\left\{ \begin{array}{l}
x + 2my - z = 1\left( 1 \right)\\
2x - my - 2z = 2\left( 2 \right)\\
x - \left( {m + 4} \right)y - z = 1\left( 3 \right)
\end{array} \right.\\
\Rightarrow \left\{ \begin{array}{l}
\left( 1 \right) - \left( 3 \right) \Leftrightarrow 2my + \left( {m + 4} \right)y = 0\\
2.\left( 1 \right) - \left( 2 \right) \Leftrightarrow 4my + my = 0
\end{array} \right.\\
\Rightarrow \left\{ \begin{array}{l}
\left( {3m + 4} \right)y = 0\\
5my = 0
\end{array} \right.\\
\Rightarrow y = 0\\
\Rightarrow \left\{ {x - z = 1} \right.\\
T = 2017x - 2018y - 2017z\\
= 2017.\left( {x - z} \right) - 2018y\\
= 2017.1 - 2018.0\\
= 2017
\end{array}$
