Answer:
And on this case we can use the product rule for a derivate given by:
Where 
and 
And replacing we have this:
Step-by-step explanation:
We assume that the function of interest is:
And on this case we can use the product rule for a derivate given by:
Where and
And replacing we have this:
1. Annual percent increase in rent is basically just a percentage of the rent increased each year.
2. Heater: Use fire places, or lower the amount of air conditioning usage so it's not so cold.
Electricity: Turn off ceiling fans and lights when not used, or only allow the essential things to use electricity.
Water: Not leave faucets or showers running, or no bathtubs which prevents baths.
3. The couple could save $450 in one year because 3000 divided by 0.15 which is the 15%, equals to the total amount saved at $450.
4. Groceries/everyday essentials, Gas money, taxes, pay off loans.
If your turn 3/5 into 6/10 it becomes easier to turn into a decimal or a percentage.
3/5 = 0.60 = 60%
