Key Features
Growth or Decay
Compound Interest
Rate
Applications
100
If, y=a(bx), what is a?
a=initial amount/y-intercept
100
How can a student determine if an equation represents exponential GROWTH or DECAY if the equation form is
y=a*b^x
If the b is in between 0 and 1, the equation represents exponential decay.
100
What does n represent in the compound interest formula?
Number of times compounded
100
Stated as a percent, what is the growth/decay rate?
y=5(0.5)^x
50%
100
Is the function exponential growth or decay? 
Decay
200
Select all equations that are NOT exponential functions:
A. f(x) = 5x D. f(x) = 2x-1
B. y =4x E. y = 7.1x
C. y = 2 * (4)x F. f(x) = 2/5x + 3
B D F
200
f(x)=.25(1.3)x
Does this functions represent exponential growth or decay? What is the percent growth/decay rate?
TWO ANSWERS
Exponential Growth
30%
200
What is the formula for compound interest?
200
Stated as a percent, what is the growth/decay rate?
y=5(1.3)^x
30%
200
CALCULATOR READY
y=2300*0.995^x
models the enrollment in a high school, where x is the number of years after 2025. What will the enrollment be in 2030?
2243
300
Does the graph reflect exponential growth, exponential decay, or neither?
Exponential Growth
300
f(x)=a(0.93)x
Does this functions represent exponential growth or decay? What is the percent growth/decay rate?
TWO ANSWERS
Exponential Decay
7%
300
CALCULATOR READY
If you put $500.00 into an account and the account earns 3% interest, compounded quarterly. How much will be in the account after 5 years?
$580.59
300
Stated as a percent, what is the growth/decay rate?
y=(0.01)^x
99%
300
CALCULATOR READY
What will be the cost in 17 years?
$32,313.27
400
What is the MAIN difference between linear functions and exponential functions?
Linear functions have has a constant rate of change.
Exponential functions have an exponent.
400
CALCULATOR READY
Ms. Wiggins purchased a car for 26,400 and every year the value decays by 12%. What can she expect the value of her car to be after 3.5 years?
f(x)=26400(.88)3.5=$16,876.92
400
CALCULATOR READY
Cali borrowed $95 for a year at 5.2% interest that is compounded semi annually. How much will she have to pay back?
$100
400
Is this exponential growth or decay?
Stated as a percent, what is the growth/decay rate?
y=1/2(0.7)^x
TWO ANSWERS
Decay. 30%
400
CALCULATOR READY
16,941 people
500
What is the y-intercept and horizontal asymptote? TWO ANSWERS
y-intercept = (0, 1)
asymptote = y=0
500
CALCULATOR READY
Annual sales of a fast food restaurant are $530,000 and increasing at a rate of 5%. What will the annual sales be in 6 years?
y=
a*b^x
530,000(1.05)6 =$710,250.69
500
CALCULATOR READY
Adam invests $500 in a retirement account with a fixed annual interest rate compounded monthly. After 2 years, the balance reaches $520.39. What is the interest rate of the account?
2%
500
Identify the starting value, growth or decay, rate of growth/decay, and amount of time (years) in the following function (FOUR ANSWERS)
y=2500(0.67)^4
Starting value = 2500
Growth or Decay? Decay
Rate = 33%
Time = 4 years
500
CALCULATOR READY
represents a sample of a decaying colony of germs. How many germs will be present in 4 days?
500