Answer:
Decay
Step-by-step explanation:
Considering the model:

0.85=1-0.15
Therefore, the model can be rewritten as:

This shows that the model decays by a common ratio of 0.15 or 15%.
In general, when the common ratio is less than 1, the model decays while whenever it is greater than one, there is exponential growth.
the answer to 7 times z reduced by a third of the product is 2z