1. Warm Up 5 4 Decide growth or decay, then name the y-intercept.
 1. y = 2(5)x 2. y = 0.999x 3. y = 5( )x   5 4

2. HW Review

3. Let's Remember: Exponential Growth vs. Exponential Decay
b > 1 (growth factor) 0 < b < 1 (decay factor)
b = 1 + % (as decimal) b = 1 -- % (as decimal)

7. Practice
- back of notes

8. Exponential Growth/Decay Practice Problems
Extra
Exponential Growth/Decay Practice Problems
1. You deposit $800 into an account that pays 6% interest.
Find the account balance after 8 years.
2. The population of a city in 1998 was 100,000. The population has been
decreasing by 2% per year ever since. Find the population after 5 years.
3. A business had a profit of $18,000 in 1995 and increased by 10% per year.
Find the profit of the company after 7 years.
4. You buy a used truck for $13,000. It depreciates at a yearly rate of 18%.
Find the value of the truck 5 years later.

9. Exit Ticket 1. A town with a population grows 3% per year.
Find the population at the end of 10 years.
2. A $1000 purchase loses 10% of its value each year.
How much will it be worth in 5 years?
3. Suppose you invest $1500 in an account paying
4.75% annual interest. Find the account balance
after 25 years with the interest compounded quarterly.
**Remember to use the interest formula: