How to get my grades up in 2 weeks?

So my other grades are A's but I have History and Science that are So close to being A's (for the semester). My history grade is 87 but the semester grade is 89 and my science grade is 87 but the semester grade is 88. I need my regular history grade to be at least 90 to make my semester grade to be an A. I need my science grade to be at least 91 or 92 to make my semester grade to be an A. This might seem confusing but it also takes in my nine weeks' grade from earlier. Yeah, thats probably confusing too.
But anyways the school year is almost over and my mom and I agreed that if I had all A's for the semester, I'd get an iPhone, something I've been wanting for So LONG. I'm so close and I can't give up but the school year ends next Friday.
Something you should know-- I'm pretty sure my science teacher isn't going to give extra credit assignments because he told me that a couple of weeks ago. I'm also not sure if we're having finals in science but i know we're in history.
Please help me! What can I do to get my grades to be all A's?!

Ask each teacher if there's anything you can do to raise your grade or how you can raise it up. Be persistent and ask everyday and study real hard for finals. Go in for tutorials every morning for each class alternating between classes. This will show you are serious.

You may be able to raise your GPA by going to those instructors in History and Science and ask if there's some special project to be done to raise your grade up a few points. However, to alert you, those instructors will not do that for you or anyone else. Instructors will say you should have studied more or done more projects. Good luck.

I was a college professor of education at four universities.