Appendix B - Coordinate Geometry and Lines - B Exercises - Page A15: 4

$\sqrt {13}$

To find the distance between $(1,-6)$ and $(-1,-3)$, we use the distance formula: $d=\sqrt {(x_{2}−x_{1})^{2}+(y_{2}−y_{1})^{2}}$. We plug in the given x and y values: $d=\sqrt {(-1−(1))^{2}+(-3-(-6))^{2}}$. We then simplify to arrive at the answer: $d=\sqrt {(-2)^{2}+(3)^{2}}=\sqrt {13}$