Question

What is the recursive formula for this geometric sequence? -2, -16, -128, -1024,

Answer 1

Answer: the answer is A

Answer 2

Answer: Choice A

The first line shown in choice A is $a_1 = -2$ which means "the first term is -2"

The next line in choice A means "the nth term ($a_n$) is found by multiplying the prior term ($a_{n-1}$) by 8". Put another way: multiply each term by 8 to get the next term.

first term = -2

second term = 8*(first term) = 8*(-2) = -16

third term = 8*(second term) = 8*(-16) = -128

fourth term = 8*(third term) = 8*(-128) = -1024

and so on.