The given equation represents equation of a circle .
The equation of circle is :
[tex] (x-h)^{2} + (y-k)^{2} =r^{2} [/tex]
where (h,k) is the center of circle and r is radius.
Now our given equation is :
[tex] (x)^{2} + (y+3)^{2} =36 [/tex]
Rewriting it in the form of equation of circle:
[tex] (x-0)^{2} + (y+3)^{2} =6^{2} [/tex]
So here radius is 6.
Answer : Tom can walk 6 miles from Darren's home and still be heard.
