This unit is about solving systems of equations by using two methods: graphing and substitution. In the first method, Graphing Systems of Equations, the system is solved by graphing the two linear equations, and then examining the graphs of the equations. If the two lines in the system intersect at one point, there is one solution (x, y). If the two lines graph on top of each other, there are many points of intersection; thus, there is an infinite number of solutions. If the lines are parallel, there is no solution because parallel lines never intersect. In the second method, Solving Systems by Substitution, algebraic manipulations are used to solve for x and y, if a solution exists.
Graphing to Solve Equations--Charity Event (02:52) 
