find an equation for the nth term of the sequence.

-2, -8, -32, -128,
a) an = 4 • -2n
b)an = -2 • 4n - 1
c)an = -2 • 4n
d)an = 4 • -2n + 1

Without any equipment, you can see stars that are 2{,}800{,}0002,800,0002, comma, 800, comma, 000 light-years away. by looking through a small telescope, you can see stars that are 3{,}112{,}000{,}0003,112,000,0003, comma, 112, comma, 000, comma, 000 light-years away. approximately how many times as far can you see using a small telescope as without any equipment?