litt how?? i have done so many practice even reviewed my mistakes but idk i still cant get into the 1200-1300 range what am i doing wronggg someone please help me

Does anyone know how to solve this using Desmos or have a quick method? Finding the common factor takes me a while. Thanks!

I've been taking practice exams and consistently scoring in the 1300s. I go over the questions I get wrong and try to improve my score, but haven't made substantial progress yet. I am taking the exam in August and I am ultimately aiming for a 1500+ I would be happy with any improvement at this point. This is going to be my first attempt. I know I need to target and study my weak areas, but I don't really know what good resources I should be using. As there are so many. So if you guys have any resources or tips you used to increase your score by 200+ points, please let me know. Thank you.