In this tutorial the instructor shows how to find the vertices of a polygon of constraints. In any optimization problem after defining your polygon you need to find its vertices. First you will have a set of equations which represents the constraints in your problem. Now you have to find the coordinates of the vertex of it by solving the optimization problem. To do that you have to start with a point and check the lines that are passing through it. Now take those lines and solve them for the coordinates of that point. Similarly repeat these steps for the rest of the vertexes which gives the coordinates of all the vertexes of your polygon. This video shows how to optimize a pair of equations to find the vertices made by those lines.