a) Using your own words, write a practice guide for future MAT223 students learning row reduction. Your guide should include a general explanation. (b) Write three examples of systems of three equations and three variables where the systems have one, infinite, and no solutions, respectively. These matrices cannot have zero entries, and you need to justify your answer. (c) Pick one of the three examples to indicate how to apply your guide to solving the system. (d) For the example with infinite solutions, write your answer in set builder notation, and as a span