Question

Calcular  a soma dos  9 termo da P.G. (  3,-6,12,-24...):
 ​

Answer 1

Resposta:

resposta.7

Explicação passo-a-passo:

.........

aksjjdkkalkaaksnjsjskkzueira

Answer 2

Resposta:

$S_9=513$

Explicação passo-a-passo:

$a_1=3\\\\q=\frac{-6}{3}\\\\q=-2$

$S_n=\frac{a_1(q^n-1)}{q-1} \\\\S_9=\frac{3[(-2)^9-1]}{-2-1}\\\\S_9=\frac{3(-512-1)}{-3}\\\\S_9=\frac{3(-513)}{-3} \\\\S_9=\frac{3.513}{3}\\\\S_9=513$