Do 2 Parallel Lines Ever Intersect?
  to solve a system of linear equations by graphing. The first step is to graph each of the given equations, then find the point of intersection of the two lines, which is the solution to the system of equations. If the two lines are parallel, then the solution to the system is the null set. If the two given equations represent the same line, then the solution to the system is the equation of that line.