On a graph, there are two axis. The x-axis and the y-axis. These axes are usually labeled to represent the relation between two values or quantities. The vertical axis is called the y-axis and the horizontal axis is called the x-axis. These axis are related to each other and can be used to solve equations for different kinds of graphs drawn.
The gradient of the graph is also a valuable quantity that is often calculated from different coordinates of x and y-axis. They are commonly used in mathematics and to solve many arithmetic equations as well as to depict different relations.