How do you change a recursive rule to an explicit rule and back? i missed 4 questions on my test and i have the correct answers but before i take the retest i need to understand how to do this. .

You would need to know and memorize each formula(unless they are given to you during th test) and understand what each spot represents. I will try to explain. I will use number 4 as an example. So I am guessing that you understood that d=-5 because of the answer that you chose. That's good not to find the start al you do is the oppisite. You will add 5 to 47 to get 52 that's why C is correct. For number 5 I am guessing it is an exapmle of exponential growth. that formula is y=a(1+r)^t I hope you understand what each varible stands for but I will try to explain as I go. 'a' stands for the original amount so we put 2500 for that, 'r' is the rate of growth as a decimal, ou did get that but you forgot to add 1 to that. That's all. For Item 1 I don't understand sorry. Item 2 however I would use plugging in each answer. So since the answer is B you would take a1=5 and plug it in so the equation says 5=14-9(1) because n is 1 and a1 is 5. Once solve this equals 5 on both sides so it is correct so during the test I would just try that strategy for all of the answers. I hope this helped and isn't too confusing, If you have any questiions please ask.

The answer would be -3.9> -4.5