The centres of those circles which touch the circle, x2+y2−8x−8y−4=0, externally and also touch the x - axis, lie on
a parabola
Radius =√16+16+4=6
(6+k)2=(h−4)2+(k−4)2Replace h→x,k→y(y+6)2−(y−4)2=x2−8x+16(2y+2)(10)=x2−8x+1620y+20=x2−8x+16x2−8x−20y−4=0
Centre lies on parabola