Respostas

  • Usuário do Brainly
2014-03-12T22:04:09-03:00
A₁ = 7
a₂ = 21
n = 7
q = 21 ÷ 7 = 3

Sn = a₁ . (qn - 1)
           q - 1
S₇ = 7 . (3⁷ - 1)
           3 - 1
S₇ = 7 . (2187 - 1)
            3 - 1
S₇ = 7 . 2186 
            2
S₇ = 15302
          2
S₇ = 7651
 
2 5 2
2014-03-12T22:05:04-03:00
7+21+63+189+567+1701+5103= 7103