In Exercises 21 and $22,$ find a parametric equation of the line $M$ through $\mathbf{p}$ and $\mathbf{q} \cdot[\text { Hint: } M \text { is parallel to the vector } \mathbf{q}-\mathbf{p} . \text { See the }$ figure below.
$$
\mathbf{p}=\left[\begin{array}{r}{-6} \\ {3}\end{array}\right], \mathbf{q}=\left[\begin{array}{r}{0} \\ {-4}\end{array}\right]
$$