Write the explicit formula for the geometric sequence. Then find the fifth term in the sequence.
a1 = –4, a2 = 8, a3 = –16
(1 point)
Responses
an = –4 · (2)n; –64
a n = –4 · (2) n ; –64
an = –4 · (–2)n–1; –64
a n = –4 · (–2) n–1 ; –64
an = –4 · (–2)n; 128
a n = –4 · (–2) n ; 128
an = –2 · (–4)n–1; –51
The correct answer is:
an = -4 · (-2)n-1 ; -64