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

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.

Prove that the lines (x+1)/(3)=(y+3)/(5)=(z+5)/(7) and (x-2)/(1)=(y-4)/(4)=(z-6)/(7) are coplanar. Also, find the plane containing these two lines

The lines (x-2)/1=(y-3)/2=(z-4)/(-2k) and (x-1)/k=(y-2)/3=(z-6)/1 are coplanar if