Will I Get Rescinded?

How badly do my grades need to slip this semester for my admissions offer, if I even receive one, to be rescinded? My current math grade is a D- and I don't see it getting better anytime soon. I spent well over 20 hours studying for the last test and got a 46%. All of my other grades are either solid or weighted A, but I'm afraid I won't be able to get anywhere near that in math. What do you guys think will happen if I fail this class? It's precalculus, so it isn't an A-G requirement, but it will still look bad on my transcript. Thanks for the help.