## Tabbiejack Group Title Write the explicit formula for the geometric sequence. a1 = -5 a2 = 20 a3 = -80 A. an = -5 • (-4)n B. an = -5(-4)n-1 C. an = -4(-5)n-1 D. an = -5 • (4)n one year ago one year ago

1. bahrom7893 Group Title

look a1 = -5 n=1 a2=20 n=2, etc..

2. Jhannybean Group Title

It would be B because in a geometric sequence, you have $\large ar ^{n-1}$ and in finding our r, we take $$\large\frac{ a _{2} }{ a _{1} }$$ and that is -4

3. bahrom7893 Group Title

This way you can eliminate A because term 2 doesn't match up... And I think Jhanny's right

4. Tabbiejack Group Title

thanks you that was heard

5. Jhannybean Group Title

So we have a1 = -5, our r = -4 and plug it into our formula $\large ar ^{n-1}$

6. Jhannybean Group Title

thanks bahrom :)

7. Tabbiejack Group Title

Can you help me with another

8. Jhannybean Group Title

sure

9. Tabbiejack Group Title

What is the simplified form of the expression?|dw:1369539526178:dw|

10. Jhannybean Group Title

Alright, for this one you have a variable with two different powers dividing eachother, and in this case, we can simply do this. $\large \frac{ 1 }{ q ^{\color{red}{(33/4)-8} }}$

11. Jhannybean Group Title

we you know to solve $\color{fuchsia}{\frac{ 33 }{ 4 }}-\color{green}{8}$

12. Tabbiejack Group Title

|dw:1369539985575:dw|

13. Tabbiejack Group Title

That is the choices

14. Jhannybean Group Title

hmm...something seems wrong here.

15. Jhannybean Group Title

$\frac{ 33 }{ 4 }-8*(\frac{ \color{green}{4} }{ \color{green}{4} })= \frac{ 33 }{ 4 }-\frac{ \color{darkorchid}{32} }{ \color{darkorchid}{4} }$

16. Jhannybean Group Title

Ohh I see. hm, well what do you get when you reduce 33/4- 32/4? :D

17. Tabbiejack Group Title

I am confused

18. Jhannybean Group Title

hm?

19. Tabbiejack Group Title

I have no Idea what the answer is

20. Jhannybean Group Title

solve (33/4)-(32/4) and we'll work from there, you'; get your answer, promise :)

21. Tabbiejack Group Title

I am the parent of 2 children that is failing

22. Tabbiejack Group Title

this looks like greek to me..

23. Jhannybean Group Title

ok, what is.... 3-2?

24. Tabbiejack Group Title

1

25. Jhannybean Group Title

good :) so 33-32 works the same way, it is also 1.

26. Jhannybean Group Title

So we now have $\frac{ 1 }{ q ^{\color{blue}{1/4}} }$

27. Tabbiejack Group Title

o ok

28. Tabbiejack Group Title

I thank you so much

29. Tabbiejack Group Title

algebra has always been my worst subject

30. Jhannybean Group Title

It'll get better with practice :) Practice makes people perfect in math ^_^

31. Tabbiejack Group Title

I remember hearing that when I was young

32. Tabbiejack Group Title

I have another quesiton if you are up to it?

33. Jhannybean Group Title

Of course :) Math is a lot about understanding a problem as a whole and finding a relation to a technique method in solving, it's all patterns.

34. Jhannybean Group Title

sure thing

35. Tabbiejack Group Title

I have 2 test to give to my children for the summer to help them prepare for summer school that is why I am getting the answers so I will be able to help them

36. Jhannybean Group Title

Interesting

37. Tabbiejack Group Title

What is the simplified form of the expression?|dw:1369541274406:dw|

38. Jhannybean Group Title

$\large (3x ^{\color{forestgreen}{7/2}})^{\color{blue}{6}}(x ^{\color{green}{2}})^{\color{blue}{6}}$ here, we will start 1 part at a time. lets start with $$\large (3x ^{7/2})^{6}$$

39. Tabbiejack Group Title

ok what do we do next

40. Jhannybean Group Title

we're going to multiply 6 to the 3 AND the x^(7/2)

41. Jhannybean Group Title

Are you able to do that?

42. Tabbiejack Group Title

18 x

43. Tabbiejack Group Title

I suck

44. Jhannybean Group Title

Hm.. not exactly, we have $\large(3^{\color{blue}{6}})(x ^{\color{blue}{(7/2)(6)}})$ which gives us $\large(729x ^{21})$

45. Tabbiejack Group Title

A. 729x33 B. 3x33 C. 729x29 D. 3x29

46. Jhannybean Group Title

Now that we've taken care of the first part, we can move onto the second part, which is $\large (x ^{2})^{6} = x ^{\color{red}{6*2}}= x ^{\color{blue}{12}}$

47. Tabbiejack Group Title

ok

48. Jhannybean Group Title

Now we can combine both parts together so we get $\large (729x {^\color{green}{21}}) *(x ^{\color{green}{12}}) = 729x ^{\color{red}{21+12}}$

49. Jhannybean Group Title

50. Jhannybean Group Title

Good luck with your other problems!

51. Tabbiejack Group Title

33

52. Tabbiejack Group Title

729x^33

53. Tabbiejack Group Title

am I right?

54. Tabbiejack Group Title

thanks so much