Question

The tenth, eleventh, and twelfth terms of a sequence are shown in the table below:


Term number 10 11 12
Term 21 24 27


Which of the following shows the first five terms of the sequence?

a)9, 6, 3, 0, -3
b) -9, -6, -3, 0, 3
c) 6, 3, 0, -3, -5
d) -6, -3, 0, 3, 6

Answer 1

do you need help?

Answer 2

yessss

Answer 3

this is what kinda sequence?

Answer 4

do you notice a common difference among the terms?

Answer 5

oh theres a diffrerence of 3

Answer 6

yes!

12->27
11->24
10->21
9->21-3
8->21-3(2)
7->21-3(3)
6->21-3(4)
5->21-3(5)
4->21-3(6)
and so on
hope you can see the pattern

Answer 7

ohh i see it thank youu

Answer 8

what do you think the answer is?

Answer 9

a ?

Answer 10

5th term is 21-3(5) = ?
4th term is 21-3(6) =?
3rd term is 21-3(7) =?
2nd term is 21-3(8)=?
1st term is 21-3(9)=?

Answer 11

oh wait no its C

Answer 12

do those differences really carefully...

Answer 13

1st term gives you 21-3(9) which equals?

Answer 14

-6

Answer 15

right does c have the first term being -6?

Answer 16

which choice has the first term as -6?

Answer 17

no its d

Answer 18

right it is d

Answer 19

oh lol kk thank you

Answer 20

here is another way if you have preferred
\[\text{ Recall } a_n=a_1+d(n-1) \\ \text{ we are given } a_{10}=21 \\ a_{10}=a_1+d(10-1) \\ 21=a_1+3(10-1) \\ 21=a_1+3(9) \\ 21-3(9)=a_1 \]
just like we found the long away for a_1 here

Answer 21

wow thanks so much

Answer 22

np