Question

If the lines x-2/1=y-3/1=z-4/-k and x-1/k=y-4/2=z-5/1 are coplanar, then k can have

(a) any value

(b) exactly one value

(c) exactly two values

(d) exactly three values

Answer 1

Using fact, two line

=> k² + 3k = 0 
k = 0 or k = –3

So, k can have exactly two values