The graph for X 3 will cover all the area in which the x-coordinate's value is greater than 3 and also equal to 3.
In the above graph all the dotted area represents X > 3 and the solid line parallel to y-axis represents X = 3. Hence X 3 is the sum of dotted area and the solid line.
3 will cover all the area in which the x-coordinate's value is greater than 3 and also equal to 3.