Question

Determine o 8º termo da PG (-24, -12,...):

Answer 1

Explicação passo-a-passo:

Calculando a razão da PG(-24, -12, ...)

$q=\dfrac{a_{2} }{a_{1} }\\\\q=\dfrac{-12}{-24}\\\\\boxed{q=\frac{1}{2} }$

Usando o termo geral da PG para calcular $a_{8}$:

$a_{n}=a_{1}.q^{n-1}\\\\a_{8}=a_{1}.q^{8-1}\\\\a_{8}=a_{1}.q^{7}\\\\a_{8}=(-24).\bigg(\dfrac{1}{2}\bigg) ^{7}\\\\a_{8}=-24.\dfrac{1}{128} \\\\\boxed{\boxed{a_{8}=\frac{-3}{16} }}$

Resposta B