Yup. This is the easy answer. Why? Let's have fun. If you want to skip it go to the mathematical explanation, If you are in a room , I would like you to look at any corner of that room. read more
No, y = 0 is the same as the x-axis. The y-axis is where x = 0, and the x-axis is where y = 0. This is short, but I'm right. read more
Points above the x-axis have positive y-coordinate. Points below the x-axis have negative y-coordinate. The y-coordinate of a point measures how far the point is from the x-axis. When the y-coordinate is 0 the point is on the x-axis. The graph of the equation y=0 consists of all point (x,y) in the plane for which y=0, that is all points of the form (x,0) and that is precisely the x-axis. read more
Since x is zero, its value never changes. However 'y' can take on all the values of the number line. So, since all our numbering is based on zero as a reference, when x = 0 you get a line of 'y' values which is referred to as the y-axis. read more