30.4k views
19 votes
Soooo um what???? I think i know what to do but i dont think i know what to do.....

Soooo um what???? I think i know what to do but i dont think i know what to do.....-example-1
User Crgolden
by
4.7k points

1 Answer

8 votes

Answer:

-73

Explanation:

The first term is 5.

The common difference is -3.

The first term is given: 5

To find the next term, add the common difference.

The second term is 5 + (-3) = 2

The third term is 5 + (-3) + (-3) = -1

The fourth term is 5 + (-3) + (-3) + (-3) = -4

Notice that for each term, you start with 5 and you and -3 times 1 less than the number of the term.

The nth term is:

a_n = 5 + (-3)(n - 1)

a_n = 5 - 3n + 3

a_n = 8 - 3n

Let's test this expression for the first 4 terms:

a_1 = 8 - 3(1) = 5

a_2 = 8 - 3(2) = 2

a_3 = 8 - 3(3) = -1

a_4 = 8 - 3(4) = -4

Notice we get the same numbers we did above for the first 4 terms. This expression does work.

Now we find the 27th term:

a_27 = 8 - 3(27)

a_27 = -73

User Mdrg
by
4.9k points