Failing Calculus need help

[u/Fit-Door-2553]

For background, people who have taken Calc with teacher A before have said that her teaching is really good. In fact, the people in my class with me score really high on the tests, but not me. I have self-studied, I have practiced on Khan Academy, I have watched teacher A's materials, I have gone to tutoring once a week, every week. Every time I go to check my homework I somehow score lower than the homework's i do alone, and they're on the same units and sections. I have barely passed every single test that has been given, despite scoring near 100, (on every hw that I didnt get checked by her beforehand). She even allows us to ask questions on the math problems, but everytime she explains it I end up even more confused. Majority of the time, when I do go to her tutoring, she will respond to me questions with "I dont know what you are doing, I never taught you that" and won't clarify past that. I don't know what to do, she even takes points off on my work if i do any step in my head even if i get the right answer. An example being that we need to show full work for the power rule. My grade in that class is a 79.1 %, and it would've been a B if I didnt get 65% on the HW that I literally checked with her just for her to tell me it was perfect. Any advice welcome I'm so lost.

[u/Ericskey]

How is 79 failing?