Find the 13th term of the sequence 8, - 16, 32, - 64, ...

A) 32768 B) None of these C) - 65536 D) - 16384

This is a geometric sequence. To find the common ratio, divide the second term by the first term.

-16/8 = - 2

an = a1 * r^ (n-1)

n = term to find = 13

a1 = first term = 8

r = common ratio = - 2

a13 = 8 * - 2^ (13 - 1)

a13 = 8 * - 2^12

a13 = 8 * 4096

a13 = 32768 <===