(- 1 - 5n + a * n ^ 2) - (7n - 4n ^ 2 + 9) = 12n ^ 2 - 12n - 10 the equation above is true for all values of n where a is a constant, what is the value of a?

Bis your answer to this

It depends on the subject for me. some exams are easier than others so i usually go through it and answer questions i know based on my general knowledge, then double check after. going through the lesson can a lot  because the exams can be  very lesson-specific, but sometimes they are ridiculously long so a lot of people don't take the time. i did find that, when i went through the lessons, i was making 100's on my exams vs strictly using + the internet and  i make 90's.