Exponential Growth Decay Functions

Graph the exponential function that has a starting value of 8 and decreases by 12.5%.

Set the dotted line to y = 0.

What is the primary characteristic of an exponential decay graph?

• The graph decreases rapidly at first, then levels off.

• The graph increases rapidly at first, then levels off.

• The graph is a straight line.

• The graph is a parabola.

Is this exponential growth or decay?

• Growth

• Decay

How many fruit flies are in the population after 7 days (1 week)?

• 140 flies

• 105 flies

• 101 flies

• 735 flies

Is this exponential growth or decay?

• Growth

• Decay

• Linear

• Not a function

In an exponential function, what does the b value represent?

• Rate of growth or decay

• Growth or Decay factor

• Initial value

• Exponent

In an exponential function, what does the a value represent?

• Rate of growth or decay

• Slope

• Initial value

• Exponent

The value of a car is $15,000 and decreases at a rate of 8% per year. What is the decay factor?

• 0.08

• 0.92

• 1.08

• 8

Which of the functions shows an initial amount of $15 and an increase of 35% each year?

• y = 15(35)^x

• y = 15(0.35)^x

• y = 35(1.15)^x

• y = 15(1.35)^x

The population of mosquitoes at the beginning of the summer is 4000. The population grows at a rate of 25% a month. How many will there be after 4 months?

• 9766

• 9006

• 9765

• 5433