(when confronted by a student who complained that he was in class every day, so why was his grade so low)
"That chair is here every class too. It's also not going to pass this class!"
- Ron Breitenbach
You should assume that college-level courses (especially in mathematics) will be more challenging than the corresponding course you took in high school. It is absolutely necessary that you replace high school notions of teaching, learning, and working with college-level notions.
In college, the goal is not simply to coach you to reproduce what was said in the classroom. You are expected to understand the material at a higher level of mastery. This mastery level is determined by your professor, but should at least include an ability to take core concepts taught during the semester and expand upon them with unique, critical thought. Moreover, you should approach each concept with the thought that you may be asked to explain it to your instructor in your own words and without the luxury of notes.
As an interesting side-note, there are graduate courses titled "algebra" that are completely different than the course you took in high school. Just because they share the same name does not mean they are the same class.
My Style: I teach at the college level. Therefore, I make the assumption that students in my courses are beyond the high school mindset of "I am here, so I should pass." I expect excellence and accept, at the minimum, a solid understanding of the core concepts, but never shall I accept academic indifference and laziness.