In this video the instructor shows how to solve a system of equations by elimination method. First you need to know how many possible number of solutions you can get by solving a system of equations. There are three possibilities. In the first case there are two lines with different slopes, so they intersect at a point which is the solution to that system. In second case there can be two lines with same slope but are parallel to each other. In this case the system has no solution. In the third case too there can be two lines with same slopes but the lines can lie on one another. Now this system has infinitely many solutions. Now using these concepts you try to solve the equations and based up on the result arrive at the solutions to the system of that equations. This video shows how to solve a system of equations by elimination method.