Answer:
4
Step-by-step 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 [tex]T_1, T_2, T_3[/tex] and the common ratio with r
From the analysis above;
[tex]r = \frac{T_2}{T_1}\ or\ r = \frac{T_3}{T_2}[/tex]
Substitute -5 for [tex]T_1[/tex]; -20 for [tex]T_2[/tex]; -80 for [tex]T_3[/tex]
[tex]r = \frac{-20}{-5}\ or\ r = \frac{-80}{-20}[/tex]
[tex]r = 4\ or\ r = 4[/tex]
Both values of r are the same;
Hence, the common ratio of the sequence is 4
