Plotting Points on the Cartesian Coordinate System
We can represent a flat surface by drawing the Cartesian Coordinate System with two axes: a horizontal axis and a vertical axis. We usually call the horizontal axis "the xaxis" and the vertical axis "the yaxis." The origin of the Cartesian Coordinate System is located at the point where the xaxis and the yaxis cross.
Each point located on a flat surface can be represented with two coordinates: an xcoordinate and a ycoordinate. When we write the coordinates for a point, we put both coordinates inside of a single set of parenthesis. The xcoordinate is written first, and the ycoordinate is written second.

The xcoordinate for a point tells the location of the point to the right or to the left of the origin of the coordinate system. If the xcoordinate for a given point is positive (greater than zero), the point is located to the right of the origin, and if the xcoordinate is negative (less than zero), the point is located to the left of the origin. If the xcoordinate for a point is equal to zero, the point is located on the yaxis.
The ycoordinate for a point tells the location of the point above or below the origin of the coordinate system. If the ycoordinate for a given point is positive, the point is located above the origin, and if the ycoordinate is negative, the point is located below the origin. If the ycoordinate for a point is equal to zero, the point is located on the xaxis.
The ycoordinate for a point tells the location of the point above or below the origin of the coordinate system. If the ycoordinate for a given point is positive, the point is located above the origin, and if the ycoordinate is negative, the point is located below the origin. If the ycoordinate for a point is equal to zero, the point is located on the xaxis.