Answer:
7
Step-by-step explanation:
Let's start by converting this to standard form.
[tex]x^2+10x+y^2-4y=20\\(x^2+10x+25)-25+(y^2-4y+4)-4=20\\(x+5)^2+(y-2)^2=49[/tex]
The center of the circle is at (-5,2), and the radius is [tex]\sqrt{49}=7[/tex] units. Hope this helps!
