Plot[{4, 0}, {x, -2, 2},
     Epilog -> {Blue, PointSize@Large, Point[{1, 4}]},
     PlotStyle -> {{Red, Dashed, Thickness[0.004]}, {Red, Dashed, 
        Thickness[0.004]}},
     PlotRange -> {-1, 6}]

[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/ME4VZ.jpg