Exponential Functions

Write an equation that models the following situation:

Samantha's hair was known to grow very rapidly. It began at a length of 6 in and grew at a rate of 14% a week.

(HINT: Write out the equation on a separate piece of paper and hen simplify inside the parenthesis)

• y=6(0.14)^x

• y=6(1+14)^x

• y=6(1.14)^x

• y=6(0.86)^x

Is this exponential growth or decay?
y = 7(1.2)^x

• Growth, because of 7

• Growth, because of 1.2

• Decay because of 1.2

• Decay because of 7

Suppose a culture of bacteria begins with 5000 cells and dies by 30% each year. Write an equation that represents this situation.

• y=5000(0.7)^x
• y=30(5000)^x
• y=5000(1.3)^x
• y=5000x^x

You have inherited land that was purchased for $30,000 in 1960. The value of the land increased by approximately 5% per year. What is the approximate value of the land in the year 2011?

• $15,000.00

• $31,500.29

• $280,500.86

• $361,223.09

Is this exponential growth or decay?

• Growth because a=1

• Growth because there is no a

• Decay because b=0.5

• Neither because a=0

The population of Boringtown decreased annually by 1.8% between the year 2015-2018. In 2015, there were approximately 200,000 people living in Boringtown. Which function models the city's population since 2015?

• f(x) = 200,000(1 + 0.018)³

• f(x) = 200,000(1 - 0.18)³

• f(x) = 200,000(1 + 0.18)³

• f(x) = 200,000(1 - 0.018)³

Daniel’s Print Shop purchased a new printer for $35,000. Each year it depreciates (loses value) at a rate of 5%.

What is the initial value?

• $35,000

• 0.05

• 1.05

• 0.95

Describe this function.

• Exponential Growth

• Exponential Decay

• Linear Positive

• Exponential Growth

• Exponential Decay

• Quadratic

What is the x-intercept of the exponential function? 

• (0,1)
• (0,0)
• There is not one