Can I just memorize all the questions and answers for the FAA Written test to pass?

There was a time when that was true, but it is no longer the case. The FAA has been adding new questions in all pilot certification written tests and they no longer publish them. The majority of published questions have been changed, and more will continue to be changed. It is important to understand all of the material to pass the FAA knowledge test. Even if this were not the case, flight training is about learning to be a good pilot, ands while that includes some memorization, understanding is essential.