If the lines $\dfrac{x-4}{m} = \dfrac{y-3}{2} = \dfrac{z+2}{1}$ and $\dfrac{x-3}{1} = \dfrac{y-4}{1} = \dfrac{z+3}{m}$ are coplanar, then the values of $m$ are
Show Hint
Two lines in 3D are coplanar iff $(\overrightarrow{AB})\cdot(\vec{d_1}\times\vec{d_2})=0$. Set up the $3\times3$ determinant with $\overrightarrow{AB}$, $\vec{d_1}$, $\vec{d_2}$ as rows and equate to zero.