Question

Find the next four terms in the arithmetic sequence.

-15, -7, 1, ...
a)7,13,19,21
b) 10,19,28,37
c)9,17,25,33
d)7,15,25,37

Answer 1

To find the arithmetic sequence, we can first find it's common difference by deducting the first term by the second term:

-7-(-15)

=-7+15

=8

Therefore the common difference is 8, and to find the remaining terms we can add 8 for the respective terms.

T(4) = 1+8 =9

Therefore the answer is c)9,17,25,33.

Hope it helps!

Answer 2

Answer: c) 9,17,25,33

Explanation:

Use the equation
`a_n=a_1+d(n-1)`

Where "n" is the nth term,
`a_1` is the first term, "d" is the common difference and "n" is a integer greater than zero.

Find the common diference "d":

`d=(-7)-(-15)\\d=8`

Then we know that:

`a_1=-15\\d=8\\`

Since we need to find the next four terms and we know three terms then:

For
`n=4`:

`a_4=-15+8(4-1))=9`

For
`n=5`:

`a_5=-15+8(5-1))=17`

For
`n=6`:

`a_6=-15+8(6-1))=25`

For
`n=7`:

`a_7=-15+8(7-1))=33`