Question

If lines (x + 1)/1 = (y + 2)/λ = (z - 1)/-1 and (x - 1)/λ = (y + 1)/2 = (z + 1)/1 are perpendicular to each other than value of  is : 

(a) 0 

(b) 1 

(c) -1 

(d) 2

Answer 1

Answer is (b)