Exponential Functions - 1st

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

• y = 15(35)^x

• y = 15(1.35)^x

• y = 15(0.35)^x

• y = 35(0.65)^x

Select the exponential function(s) that show(s) decay.

• $f\left(x\right)=2\left(.35\right)^x$

• $f\left(x\right)=3\left(4\right)^x$

• $f\left(x\right)=4\left(\frac{7}{3}\right)^x$

• $f\left(x\right)=9\left(\frac{1}{2}\right)^x$

Is the pictured graph growth, decay, or linear or none?  

• Exponential Growth
• Exponential Decay
• Linear
• None

Which does y= 2(.5)^x represent?

• Exponential Growth

• Exponential Decay

Which does y=.5(2)^x represent?

• Exponential Growth

• Exponential Decay

Identify the y-intercept in the function f(x)=13(.27)^x

• (.27)^x

• .27

• 13

• 3.51

You buy a car for $45,000. Every day it loses 15% of its value. Write an equation that gives the value of the car, x days after you buy it. 

•  $f\left(x\right)=45,000\left(15\right)^x$  

•  $f\left(x\right)=15\left(45,000\right)^x$  

•  $f\left(x\right)=45,000\left(1.15\right)^x$  

•  $f\left(x\right)=45,000\left(.85\right)^x$  

Given the exponential function $h\left(x\right)=\frac{1}{4}\cdot5^x$  , what number represents the initial value?

•  $\frac{1}{4}$  

• 5

• x

• h(x)

Suppose you put $1000 into the bank, and you earn 12% interest each year. Write a function that tells the amount of money you have, M(t), after t years

• $M\left(t\right)=12\left(1000\right)^t$

• $M\left(t\right)=1000\left(.12\right)^t$

• $M\left(t\right)=1.12\left(1000\right)^t$

• $M\left(t\right)=1000\left(1.12\right)^t$

The expression $500\left(1.04\right)^t$ gives the number of mosquitoes in your backyard as a function of the number of hours that have gone by. What does 1.04 represent in this expression?

• There are 1.04 mosquitoes in your yard at the beginning of the night

• It is 104 degrees outside

• The number of mosquitoes increases by 4% every hour

• It takes you 1.04 seconds to swat a mosquito away from your face