If the straight lines `(x-1)/2=(y+1)/k=z/2 and (x+1)/5=(y+1)/2=z/k` are coplanar, then the plane(s) containing these two lines is (are)

If the straight lines (x-1)/(2)=(y+1)/(k)=(z)/(2) and (z+1)/(5)=(y+1)/(2)=(z)/(k) are coplanar, then the plane(s) containing these two lines is/are

If the straight lines (x-1)/(2)=(y+1)/(k)=(z)/(2) and (z+1)/(5)=(y+1)/(2)=(z)/(k) are coplanar, then the plane(s) containing these two lines is/are

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

Show that the lines (x-1)/2=(y-3)/-1=z/-1 and (x-4)/3=(y-1)/-2=(z-1)/-1 are coplanar. Also find the equation of the plane containing these lines.