Answer:
[tex]y=8(0.7)^x[/tex]
Step-by-step explanation:
Next, the battery life decreases by 30% per year. You didn't state if this is linear or exponential, so I'll assume exponential because linear doesn't make much sense in this case..
For an exponential function, the battery life will be decreasing by 30% over the previous year, not over the original. Decreasing by 30% is multiplying by 70%, or just 0.7.
Exponential form:
[tex]y=a(b)^x[/tex]
where a is the original value and b is the percent change.
In your question:
[tex]y=8(0.7)^x[/tex]
