## rockinhood one year ago +WILL GIVE MEDAL!+

1. rockinhood
2. rockinhood

@sweetburger ??

3. rockinhood

@Nnesha plz

4. Nnesha

days represent by n variable so just plugin the numbers to find the correct answer

5. Nnesha

|dw:1443788222785:dw|

6. Nnesha

let's try 4th one|dw:1443788458435:dw| $\huge\rm a_n=a_{n-1}+2(n+1)$ substitute n for 4 $\large\rm a_\color{Red}{4}=a_{\color{ReD}{4}-1}+2(\color{reD}{4}+1)$ 4-1 = 3 so a_{4-1} =a_3 now substitute a_3 for 10 bec after 3 days , there are 10 cells is same as a_3 =10 $a_4=10+2(5) ~~~~~~~~~~~~~~~~~~~~~~a_4=20$but we should get 16 so D is wrong now try other 3

7. rockinhood

so a. the equation is a4=a4−1+2(4) ? Or a4 = 10 - 1 + 8 or 17?

8. rockinhood

@Nnesha

9. Nnesha

it's $\huge\rm a_{4-1}= a_3$

10. rockinhood

Oh so a is 16 then??

11. Nnesha

{4-1} is base which is equal to a_3

12. Nnesha

$$\color{blue}{\text{Originally Posted by}}$$ @rockinhood so a. the equation is a4=a4−1+2(4) ? Or a4 = 10 - 1 + 8 or 17? $$\color{blue}{\text{End of Quote}}$$ a_{4-1}=a_3 so u wil get a_3 +8

13. Nnesha

now replace a_3 with its value

14. rockinhood

10_3 + 8

15. Nnesha

a_3 means 3rd term

16. Nnesha

it's not 10 with base 3

17. Nnesha

a_1= first term a_2 = 2nd term a_3= 3rd term so it's 10+8|dw:1443797343672:dw|

18. rockinhood

Oh ok

19. Nnesha

10+8 equal =18 so a isn't correct bec when we substitute 4 for n we should get 16

20. rockinhood

So now I have to check b? a_n = a_n - 1 + n^2

21. Nnesha

yep btw u can use 3rd and 2nd term :=) doesn't maatter

22. Nnesha

how did you get 9?

23. rockinhood

That was a mistake that I jsut realized lol

24. rockinhood

I just did C a_n = a_n - 1 + (n + 2) 10 + 6 Is it c?

25. Nnesha

yes right 10+6 =16!

26. rockinhood

a_n - 1 + (n + 2) a_3 + (4 + 2) 10 + 6

27. rockinhood

Yes! Thanks for the help, I'll be sure to let you know if I need help with any others :D

28. Nnesha

alright good work!