Equation of the plane containing the lines ¯¯¯r=(¯i−2¯j+¯¯¯k)+t(¯i+2¯j−¯¯¯k) ,¯¯¯r=(¯i+2¯j−¯¯¯k)+s(¯i+¯j+3¯¯¯k) is