What does the equation x = 4 represent in the set of real numbers2?

If you draw the equation x=4 in a Cartesian plane, that would just be a vertical line intersecting x=4 in the positive x-axis. Since the only given information is x, the y value is arbitrary. Therefore, all y-values that correspond to x=4 is a solution. The domain would just be + 4, and the range is from - ∞ to + ∞.