Question

arithmetic sequencing

Answer 1

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

-15, -6, 3, 12, ...

Answer 2

how do i go about beginning this?

Answer 3

well, is an arithmetic sequence
meaning between the terms there's a sum

that is, to get the 2nd term, you simply ADD SOMETHING to the 1st term

to get the 3rd term you ADD SAME SOMETHING to the 2nd term, and so on

so... what do you think is that SOMETHING?

Answer 4

look for patterns. it's an arithmetic sequence so it increases/decreases by a certain amount each term. what's the distance between each number?

Answer 5

you adding 9

Answer 6

so it would be -15 +9(n-1)

Answer 7

ok... so we know now that the difference is 9, that is, d = 9

so \(\bf a_{\color{red}{ n}}=a_1+({\color{red}{ n}}-1)d
\qquad
d=9\qquad a_1=\textit{1st term}=-15
\\ \quad \\
a_{\color{red}{ n}}=-15+({\color{red}{ n}}-1)9\)

yeap

Answer 8

yay thank you c:

Answer 9

yw