Question

Find an equation for the nth term of the arithmetic sequence.

a15 = -53, a16 = -5

a. an = -725 - 48(n - 1)

b. an = -725 + 48(n + 1)

c. an = -725 + 48(n - 1)

d. an = -725 - 48(n + 1)

Answer 1

find the common difference(d) first, its the difference between the consecutive terms
\(\large d = a_{16}-1_{15} = ... ? \)

Answer 2

i meant
\(\large d = a_{16}-a_{15} = ... ?\)

Answer 3

48

Answer 4

thats correct, d = 48
now we just need first term a1

use the general n'th term formula
\(a_n = a_1 + (n-1)d \\ a_{16} = -5 = a_1+(16-1)\times 48\)

can you find a1 from there ?

Answer 5

-725

Answer 6

thats correct :)

Answer 7

so is the answer an = -725 + 48(n - 1)

Answer 8

yes it is! :)

Answer 9

thxx

Answer 10

wlcmxx