Copyright/Trademark laws?

I own a postsecondary school and use several books to teach from. In the past I have had my students buy the books but we only use a few sections from each. My question is can I teach from a book the students don't purchase? Can I make copies of the pages we use so they can follow along or read a few sections at home in preparation for cl lecture? How does copyright play into this? Thank you for your time. If possible please include a source for your answer!