Red pill me on Statics and Partial Fraction Differential Equations (PDE).

I'm a junior in Mechanical Engineering who's starting to take the STEM classes now. My major consist of a lot of Statics and math. I also heard PDE is one of the hardest classes in my major. What are the two subjects about? How do I prepare and study for these subject? The professors who are teaching these courses suck too, so I'm gonna have to self-study most of this. Also I'm not too good in math since I went to shit schools in the ghetto and haven't been taught math properly since 8th grade.