Question

HELP PLEASE!
Find an equation for the nth term of the arithmetic sequence.
a16 = 21, a17 = -1

Answer 1

nth? or ninth haha

Answer 2

you have to give me a1 to be able to make the equation

Answer 3

you have two terms in a sequence, you can solve for the common difference between \(a_{17}\) and \(a_{16}\)...

Answer 4

then you can solve the first term \(a_1\) using either of the two given terms....

Answer 5

\[a_n=a_1+(n-1)d\]

Answer 6

to find d... \[d=a_{17}-a_{16}\]

Answer 7

to find \(a_1\)... you can plug in \(a_{17}\) or \(a{16}\) in place \(a_n\)...

Answer 8

this is arithmetic sequence...

Answer 9

Okay I got \[a _{15}\] what do I next?

Answer 10

How do I solve for \[a_{1}\]?

Answer 11

Is it 22?