It turns out there was a "Maths for Machine Learning" specialization on Coursera, so I signed up for and hot damn, this is fun. One of the early quizzes was solving systems of equations for two and three variables; it took a bit of work to remember how to do it (not using the A \ b trick). The early part is all just going over vectors, which I have a pretty solid handle on, so it's going quickly. We'll see how it goes when things pick up.
I also got back on track with the algorithms class.
But yeah, mostly maths the past couple of days. I'm excited; once I get through the LA stuff, I can start taking a crack at the Rigetti QVM stuff again.