If the centre of the circle 2x2+pxy+qy2+2gx+2fy+3 = 0 is (1,-3), then the radius of the circle is
17
2x2+pxy+qy+2gx+2fy+3 = 0
⇒2x2+2y2+2gx+2fy+3
⇒x2+y2+gx+fy+(32) = 0
C = (−g2,−f2) = (1,-3) , g = -2,f = 6
C=(1,-3)
r=√4+36−32 = √772