Question 471426
the equation in Standard Form {{{(x-a)^2+(y-b)^2=R^2, the Center is (a,b), the Radius is R

{{{x^2+y^2-4x-2y-15=0}}}
{{{(x^2-4x)+(y^2-2y)-15=0}}}
{{{(x^2-2*x*2+2^2)-4+(y^2-2*y*1+1^2)-1-15=0}}}
{{{(x-2)^2+(y-1)^2-20=0}}}
{{{(x-2)^2+(y-1)^2=20}}}
the Center is (2,1), the Radius is {{{R=sqrt(20)}}}