It is incredibly unreasonable for you to request that something that we've been covering in class for the last MONTH not be on the final 'cause you're having trouble understanding it.
It is NOT unreasonable for it to be on the final because it's on the syllabus, you've had at least 4 lectures on it, 3 lab sessions on it, and an auto-graded homework that's a straight up final review on it. It really doesn't matter that the tenured faculty doesn't cover it, I'm working with the syllabus poor little adjunct me was told to teach.
Look, I'm sorry it's hard and you don't get it and I've tried my hardest to help you learn it, but it's on ya'll to either learn it on your own, come to office hours/make an appointment with me, or ask questions in class.
I may end up self-destructing this. I'm just super cranky right not.