Giải thích các bước giải:
\(\begin{array}{l}
6a)M\left( {3;2} \right) \Rightarrow a.3 + b = 2\\
N\left( {4; - 1} \right) \Rightarrow a.4 + b = - 1\\
\Rightarrow \left\{ \begin{array}{l}
3a + b = 2\\
4a + b = - 1
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
a = - 3\\
b = 11
\end{array} \right.\\
b)\left( d \right)//\left( {d'} \right) \Leftrightarrow \left\{ \begin{array}{l}
a = 3 - a\\
2 - b \ne b
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
a = \dfrac{3}{2}\\
b \ne 1
\end{array} \right.
\end{array}\)
