x2+y2−2x−2λy−8=0
⇒(x2+y2−2x−8)−2λy=0, which is of the form of S+λL=0
All the circles passing through the point of intersection of circle x2+y2−2x−8=0 and y=0
Solving we get x2−2x+8=0 or (x−4)(x+2)=0
⇒A≡(4,0) and B≡(−2,0)
⇒ Distance between A and B is 6.