Answer:
4
Explanation:
Given
-5, -20, -80, .....
Required
Determine the common ratio
The common ratio of a sequence is determined by dividing a term by its immediate previous term;
Let the term be represented with
and the common ratio with r
From the analysis above;
![r = (T_2)/(T_1)\ or\ r = (T_3)/(T_2)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/lwmfj7sfqoks8ex1pohaikdy7r8evdn3qs.png)
Substitute -5 for
; -20 for
; -80 for
![T_3](https://img.qammunity.org/2021/formulas/engineering/college/k54l8mxim5dcaexuvhsjulosyoueo3zdex.png)
![r = (-20)/(-5)\ or\ r = (-80)/(-20)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/q09181pt7iv0c0olz66ozp97fssbppilb8.png)
![r = 4\ or\ r = 4](https://img.qammunity.org/2021/formulas/mathematics/middle-school/38xa098yi8cug6mb169gdx415onurys0up.png)
Both values of r are the same;
Hence, the common ratio of the sequence is 4