Question

If the lines ax + y + 1 = 0, x + by + 1 = 0 and x + y + c = 0 (a, b, c being distinct and different from 1) are concurrent, then \((\frac1{1-a}) + \frac 1{1-b} + \frac 1{1-c}=\) 

(a) 0

(b) 1

(c) \(\frac 1{a+b+c}\)

(d) None

Answer 1

Correct option is (b) 1