jmc

The first circle is centered at $(9,5)$ and has a radius of $\sqrt{6.25}=2.5$. The second circle is centered at $(-6,-3)$ and has a radius of $\sqrt{49}=7$. To find the shortest distance between the circles, we draw a segment connecting their centers, and subtract off the radii of the two circles. The distance between the centers of the circles is $\sqrt{(9-(-6){)}^2+(5-(-3){)}^2}=\sqrt{15^2+8^2}=17$. So the shortest distance between the circles is $17-2.5-7=\boxed{7.5}$.