The distance $d$ of a point $P$ to the line through points $A$ and $B$ is the length of the component of $\overline{AP}$ that is orthogonal to $\overline{AB}$, as indicated in the diagram.
So the distance from $P = (-3, 2)$ to the line through the points $A = (0, -1)$ and $B = (4, -5)$ is $\frac{6}{2\sqrt{13}}$.