which choice is the simple formula for the nth term of the following arithmetic sequence?
5,1, -3, -7, -11,...
A. -4n+9
B. 4n+1
c. 4n+9
d. -4n+1
e. 5n+4

Question

jdoe0001 · Answer

what do you think is the difference from term to term?
what makes the 2nd term 1, the 3rd term -3 and the 4th term -7?

anonymous · Answer

They are all being subracted by 4.

anonymous · Answer

**subtracted

jdoe0001 · Answer

ahhh, well then, the $\bf \text{ common ratio = -4}$
so use that in the sequence equation

$\bf \large \color{blue}{a_n = a_1 +(n-1)d}\
a_n = n^{th} \text{ term}\
a_1 = \text{ 1st term in the sequence}\
d = \text{common ratio}$

anonymous · Answer

that would make it -4n+9

jdoe0001 · Answer

$\large \bf a_n = 5 +(n-1)(-4) \implies a_n = 5 +(-4n+4)$

jdoe0001 · Answer

so simplifying that, will give us?

anonymous · Answer

-4n+9

jdoe0001 · Answer

yes