If abc−2=bc+cb where a, b, c > 0 then family of lines ax+by+c=0 passes through the point
(1,1)
(1,-2)
(-1,2)
(-1,1)
a−2bc=b+c
⇒(b+c)2−(a)2=0 or b+c−a=0 (∵b+c+a≠0)
∴ax+by+c passes through the fixed point (-1, 1)