Question

Identify the 16th term of a geometric sequence where a1 = 4 and a8 = -8,748. (2 points)
Question 1 options:

1) -172,186,884

2) -57,395,628

3) 57,395,628

4) 172,186,884

Answer 1

can you help me @shamim ?

Answer 2

We can express a geometric sequence as :
$$ \Large{ a_n = a_1\cdot r^{n-1}~,~~ n=1,2,3..} $$Now plug in the values given.

Answer 3

plug in a1 = 4

Answer 4

whats for r ?

Answer 5

we can solve for r

Answer 6

i dont understand this

Answer 7

$$\Large{
a_n = a_1\cdot r^{n-1}
\\~\\ a_1 = 4 ~, ~ a_8 =-8748
\\~\\\Rightarrow ~ a_n = 4\cdot r^{n-1}
\\~\\\Rightarrow ~ a_8 = 4\cdot r^{8-1}
\\~\\\Rightarrow ~ -8748 = 4\cdot r^{8-1}
}$$

Answer 8

what do I do after that? @jayzdd

Answer 9

-2187 @jayzdd

Answer 10

$$
\Large{
a_n = a_1\cdot r^{n-1}
\\~\\ a_1 = 4 ~, ~ a_8 =-8748
\\~\\\Rightarrow ~ a_n = 4\cdot r^{n-1}
\\~\\\Rightarrow ~ a_8 = 4\cdot r^{8-1}
\\~\\\Rightarrow ~ -8748 = 4\cdot r^{8-1}
\\~\\\Rightarrow ~ \frac{-8748}{4} = r^{8-1}
\\~\\\Rightarrow ~ \frac{-8748}{4} = r^{7}
\\~\\\Rightarrow ~ -2187 = r^{7}
\\~\\\Rightarrow ~ (-2187)^{1/7} = r
\\~\\\Rightarrow ~ -3= r
}

$$

Answer 11

yeah then what do I do ?

Answer 12

@jayzdd

Answer 13

$$
\Large{
a_n = a_1\cdot r^{n-1}
\\~\\ a_1 = 4 ~, ~ a_8 =-8748
\\~\\\Rightarrow ~ a_n = 4\cdot r^{n-1}
\\~\\\Rightarrow ~ a_8 = 4\cdot r^{8-1}
\\~\\\Rightarrow ~ -8748 = 4\cdot r^{8-1}
\\~\\\Rightarrow ~ \frac{-8748}{4} = r^{8-1}
\\~\\\Rightarrow ~ \frac{-8748}{4} = r^{7}
\\~\\\Rightarrow ~ -2187 = r^{7}
\\~\\\Rightarrow ~ (-2187)^{1/7} = r
\\~\\\Rightarrow ~ -3= r
\\~\\\Rightarrow ~a_n = 4\cdot (-3)^{n-1}
\\~\\\Rightarrow ~a_{16} = 4\cdot (-3)^{16-1}
}
$$

Answer 14

B?

Answer 15

@jayzdd

Answer 16

yes thats correct

Answer 17

Thank you so much @jayzdd

Answer 18

Identify the 31st term of an arithmetic sequence where a1 = 26 and a22 = -226. (2 points)
Question 2 options:

1) -334

2) -274

3) -284

4) -346

Answer 19

can you help me with this one @jayzdd

Answer 20

can you help me with this one @jayzdd