This document discusses how to graph and solve systems of linear equations in two variables by determining whether the system has one solution, many solutions, or no solution. It explains that a consistent system has a solution, an inconsistent system has no solution, an independent system has one solution, and a dependent system has infinitely many solutions. It also notes that a system will have one solution if the lines cross once, no solution if the lines are parallel, and infinitely many solutions if the lines are the same.