Line

A line in the euclidean sense is defined as the shortest distance between two points. In the cartesian coordinate system it is usually described as an equation in x and y of the form $y=mx+b$ where m is the slope of the line and b is the y-intercept. Any two points define a line, and given specific $(x_1,y_1)$ $(x_2,y_2)$ one can solve for the line's equation.