Respostas

2013-11-30T10:25:01-02:00
(2x/3)+(4x/9)+(8x/27)+(16x/81)+.... = 12
a1 = 2x/3
q = a2/a1 = (4x/9)/(2x/3) = (4x/9).(3/2x) --> q = 2/3
Sn = a1/(1-q)
12 = (2x-3)/(1-2/3)
12 = (2x-3)/(3/3-2/3)
12 = (2x-3)/(1/3)
(2x-3).3 = 12
2x-3 = 12/3
2x-3 = 4
2x = 4+3
2x = 7
x = 7/2