Talk to your teacher. If he's a decent guy then just show him you really want to pass and he will appreciate the effort you put into it. I'm sure he'll help you out. If not, talk to peer tutors, or your parents, and get a real tutor.
Not good at math. I got a 27 on my ACT prep test because of math. Got a 36.2 on reading and something similar on science and english. The reason people in Asia are generally better at match then americans is because they treat math like sports; it isn't something you can or cannot do, you just have to practice and improve.