Question 473097
{{{(x-6)^2+(y+5)^2=21}}}

it's a circle

for a circle with center (j, k) and radius (r):
   

{{{ (x-j)^2 + (y-k)^2 = r^2}}}

so, you have center (j, k)=(6,-5) and radius {{{r=sqrt(21)=4.58}}}

*[invoke Plot_a_circle 6, -5, 4.58]