Please help me, Ive been on this for almost half an hour ;( which explicit formula describes the sequence −9, −3, 3, 9, 15, …?

Group of answer choices

an = 9n + 6

an = 6n + 15

an = 6n - 15

an = 9n – 6

it's 9n + 6

Step by step :

-9 + 6 = -3

-3 +6 = 3

3 + 6 = 9

9 + 6 = 15

part d

step-by-step explanation:

theresa talked her parents into getting sd cards for her phone and her brother’s phone. inserting an sd card into a phone gives it more storage. they both get 8-gigabyte sd cards. how many bits of storage come with each sd card? type your answer in both scientific and standard notation.