The formula of a distance between two points:
[tex]d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]
We have the points (-1, -3) and (-9, 2). Substitute:
[tex]d=\sqrt{(-9-(-1))^2+(2-(-3))^2}=\sqrt{(-8)^2+5^2}=\sqrt{64+25}=\sqrt{89}[/tex]