1. Exponential Growth and Decay

2. Multiplier for a Percent Increase
Change the percent increase to a decimal and add the result to 1.
Example: What is the multiplier for a 5% increase?
First Step:
Second Step: . . .
5.% =
0.05 2 1
Multiplier

3. Multiplier for a Percent Decrease
Change the percent decrease to a decimal and subtract the result from 1.
Example: What is the multiplier for a 17% decrease?
First Step:
Second Step: . .
17.% = .
0.17 2 1
Multiplier

4. A = P ( 1 + r ) t Exponential Growth A: Amount after time t
P: Principle (starting amount)
t: Time after starting point
r: Decimal increase (% ÷ 100)

5. A(t) = P ( 1 – r ) t Exponential Decay
A(t): Amount as a function in terms of t
P: Principle (starting amount)
t: Time after starting point
r: Decimal decrease (% ÷ 100)

6. Growth and Decay
The area of a rain forest is 20,000,000 square miles. Every year, 11% of the rain forest will be destroyed. Write an equation that will find the remaining area y of the rain forest after x years.
y = 20,000,000 ( .89 )x

7. V(x) = 10,000 ( 1.08 )x Growth and Decay
Chet is going to put $10,000 into a bank account. Every year the value of the account will increase by 8%. Write a function V that will determine the value of the account after x years.
V(x) = 10,000 ( 1.08 )x

8. Growth and Decay
The population of people in Upper Darby is 2,000,000. Every year the population will decrease by 19%. Write an equation y that will predict the population after x years.
y = 2,000,000 ( .81 )x

9. V(x) = 165,000 ( 1.035 )x Growth and Decay
The value of a home worth $165,000 will increase by 3.5% every year. Write a function V that will predict the value of a home after x years.
V(x) = 165,000 ( )x