Y = x^2 - 5x + 3 5x + y = 39
Which of the following is the x-value of a solution to
the system of equations above?
A) 6
B) 12
C) 18
D) 36

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. 

The answer should be d if i’m wrong i’ll change my answer and fix it for you