Question

Can you guys help me with this?

Answer 1

Answer:

We have been given many sequences below:

The sequence is said to be geometric if there is same ratio between consecutive terms

$\frac{a_n}{a_{n-1}}$

So we will check all the sequences one by one:

(1) $\frac{-9}{-2.7}=\frac{10}{3}$

$\frac{-30}{-9}=\frac{10}{3}$

$\frac{-100}{-30}=\frac{10}{3}$.

Hence, geometric

(2) $\frac{2.5}{-1}=-2.5$

$\frac{-6.25}{2.5}=-2.5$

$\frac{15.625}{-6.25}=-2.5$

Hence, geometric.

(3) $\frac{9.2}{9.1}=0.010$

$\frac{9.3}{9.2}=0.010$

$\frac{9.4}{9.3}=0.010$

Hence, geometric.

(4) $\frac{0.8}{8}=0.1$

$\frac{0.08}{0.8}=0.1$

$\frac{0.008}{0.08}=0.1$

Hence, geometric.

(5) $\frac{-4}{4}=-1$

$\frac{-12}{-4}=3$

Ratio is not same hence, not geometric.