Find the equation of the circle circumscribing the triangle formed by the lines L1 = 0, L2 = 0 and L3 = 0
L1L2 + λL2L3 + μL3L1 = 0
Family of circles circumscribing a triangle whose sides are L1 = 0, L2 = 0 and L3 = 0 is
L1L2 + λL2L3 + μL3L1 = 0- - - - - - (1)
It is the definition of family of circle & circumscribing a triangle.
Equation (1) is a equation of circle so, it should follow following conditions
(1) coefficient of xy = 0
(2) coefficient of x2 =coefficient of y2
Option B is correct