From 11:00PM PDT on Friday, July 1 until 5:00AM PDT on Saturday, July 2, the Shmoop engineering elves will be making tweaks and improvements to the site. That means Shmoop will be unavailable for use during that time. Thanks for your patience!
What are we going to do with these matrices now that we've made them our faithful servants? Use them to solve equations, that's what. We'll add 'em, we'll subtract 'em, and we'll stare at 'em. Why don't you just take a picture? It'll last longer.