The two lines must be parallel, skew or intersect lines.
If the two lines are parallel, the direction vectors of both the lines are scalar multiples of each other.
The two lines\({L_1}\)and \({L_2}\)are in the form of parametric equations.
The direction vector of line\({L_1}\left( {{{\rm{v}}_1}} \right){\rm{ is }}\langle - 12,9, - 3\rangle .\)
The direction vector of line\({L_2}\left( {{{\rm{v}}_2}} \right){\rm{ is }}\langle 8, - 6,2\rangle .\)
The direction vector of line\({L_{\rm{I}}}\left( {{{\rm{v}}_1}} \right)\)is also written as follows.
\(\begin{array}{l}{{\rm{v}}_1} = - \frac{3}{2}\langle 8, - 6,2\rangle \\ = - \frac{3}{2}{{\rm{v}}_2}\end{array}\)