Trong không gian $Oxyz$, cho hai điểm $M\left( 1;2;3...

Ta có \)">\Delta JHM=\Delta JKNJM=JN.JMNx+y+z-9=0.J\in \Delta \Delta \subset \left( P \right)J\in \left( P \right):x+2y+3z-14=0.J\left\{ \begin{array}{*{35}{l}}
x+y+z-9=0 \\
x+2y+3z-14=0 \\
\end{array} \right.\Leftrightarrow \left\{ \begin{array}{*{35}{l}}
x=t \\
y=13-2t \\
z=-4+t \\
\end{array} \right..$