When solving a system of linear equations, there are essentially 3 possibilities: 1 solution, 0 solutions, or infinitely many solutions.  After demonstrating that our system is of the later variety, I show you how this question basically parameterizes the general solution to the system in terms of r.  This could just as easily been written in terms x or in terms of y.  Rather than relying on your favorite AI chatbot, you can use Desmos to answer the question for you.  In the final part of the video, I demonstrate why answer choice A is wrong and in the process teach you a bit about parametric equations.  Duration: 23:45