Question

A somas dos sete primeiros da PG (16,18,54,...) é:
a) 6558
b)5865
c)5586
d)8655
e)8565​

Answer 1

(6, 18, 54) => correto

s = a1.(q^n -1) / q-1

s = 6.(3⁷ -1) / 3-1

s = 6.(2187 -1)/ 2

s = 3.(2186)

s = 6558