Will I still be promoted to 10th grade if I fail my Algebra 1 EOC?

Never heard of a EOC. Googled it and nothing came up that was related to school.

You need to ask your school the consequences of not passing an exam. We have absolutely no way of knowing.

You have an 80 in the class, so obviously you are  understand some  of the material. 

You were in virtual school, right? Not home-schooled. That is, you had the teacher from your usual school on your device, in Teams or whatever. I know that it was harder for students to ask questions and get help with this system. The schools know that, too. Many are being a little more lenient with grades because of that. Typically, when you fail a class in high school, you get the chance to make it up in summer school. You don't repeat the grade. If you don't pass it, you just don't get the credits for it, and that will delay your graduation. If the rule is that you have to pass the test to graduate, then you just have to pass it before the end of your senior year. Georgia has other tests like that, too- many students take them several times before passing, but they can usually manage to pass before graduation. 

please ask guidance department at the school.  we haven't a clue