Question 819410
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Hi,

Standard Form of an Equation of a Circle is {{{(x-h)^2 + (y-k)^2 = r^2}}} 
where Pt(h,k) is the center and r is the radius
x^2+y^2+4x-4y-1=o      |Completing square
(x+2)^2 - 4 + (y-2)^2 - 4 - 1 = 0
(x+2)^2  + (y-2)^2 = 9 
  r = 3