In each case, determine whether or not the lines have a single point of intersection. If they do, give an equation of a plane containing them. a) r = (51, 21 - 1,3r - 3) and ra = (1 - 6, -( + 5,1 -9) bj ri = (4r. -41 + 1,1 - 5) and ra = (2t - 3, -1, -1 - 1) (Express numbers in exact form. Use symbolic notation and fractions where needed. Enter DNE if lines do not intersect.) (a) the equation of the plane: (b) the equation of the plane