a. Show that the lines $L_{1}: \vec{r}=(-2,3,4)+s(7,-2,2), s \in \mathbf{R},$ and $L_{2}: \vec{r}=(-30,11,-4)+t(7,-2,2), t \in \mathbf{R},$ are coincident by writing each
line in parametric form and comparing components
b. Show that the point (-2,3,4) lies on $L_{2}$. How does this show that the lines are coincident?