Question

HELP! 15 POINTS!

Answer 1

It's pretty easy to go through the choices and none has a[2]=-36 and a[5]=2304.  Something's probably wrong with the way the question is typed, but I will answer what's written.

$a_n = a + (n-1) d$

$a_2 = -36 = a + d$

$a_5 = 2304 = a + 4d$

Subtracting,

$2340 = 3d$

$d = 2340/3 = 780$

$a = -36 - d = -36 - 780 = -816$

Answer: a[n] = -816 + 780(n-1)  which is none of the above

Check:

$a_2 = -816 + 780= -36 \quad\checkmark$

$a_5 = -816 + 780(4) = 2304 \quad\checkmark$