Question

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

a19 = -92, a20 = 6

Answer 1

@jim_thompson5910

Answer 2

@phi @precal @Zarkon

Answer 3

@Chooch146

Answer 4

what is the definition of an arithmetic sequence? type it here what you got in your book

Answer 5

A sequence made by adding some value each time.

Answer 6

ok.
so, you have the first value \(a_1\), then you add some quantity \(C\).
\(a_2=a_1+C\), \(a_3=a_2+C = a_1 + 2C\)... etc.

you can compute \(C\) right now, since you have to adjacent value of the sequence. what do you get?

Answer 7

since \(C\) is teh value you added to go from -92 to 6, \(C=98\).
then, you use the formula \(a_n = a_1 + (n-1)C\) and the fact that you know that \(a_{20}=6\) to get \(a_1\). good luck.