Resposta :
Sn = a1/(1-q)
q = (x/3)/x
q = (x/3).(1/x)
q = 1/3
a1 = x
12 = x/(1-1/3)
12 = x/(3/3-1/3)
x/(2/3) = 12
x = 2/3 . 12
x = 24/3
x = 8
q = (x/3)/x
q = (x/3).(1/x)
q = 1/3
a1 = x
12 = x/(1-1/3)
12 = x/(3/3-1/3)
x/(2/3) = 12
x = 2/3 . 12
x = 24/3
x = 8