Exponential Function

Which of the following is an exponential function?

• y = x²

• f(x) = 3x³

• y = x³

• f(x) = 3^x

What is the initial value in y=4(2)^x

• 4

• 2

• x

What is the starting amount in the problem below?

f(t) = 300(1.05)^t

• 300

• 1.05

• t

• y

What is the growth rate in the problem below?

f(t) = 300(1.05)^t

• 300

• 1.05

• 5%

• 105%

Is this exponential growth or decay?

• Growth
• Decay

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

• Exponential Growth
• Exponential Decay
• Linear
• None

A new savings account is opened with $400 and gains 3% every year. What is the exponential function?

• f(x)=400(1+3)^x
• f(x)=400(1-0.03)^x
• f(x)=400(1+0.03)^x
• f(x)=400(0.03)^x

What is it about the equation y = 2(9/7)^x that indicates that it is a model for exponential growth?

• The equation is growth because 2 is positive.

• The equation is growth because the factor is positive.

• The equation is growth because the factor is greater than one.

• The equation is growth because the exponent is always positive.

Consider the equation y=200(1.08)^x which models the increase in value of an autographed Annie program. Let y = the value of the item, let x = the number of years since the performance. What does the 1.08 in the equation indicate?

• The value of the item is increasing by $1.08 each year.

• The value of the item is increasing by 1.08% each year.

• The value of the item will increase to $200 1.08 years after purchase.

• The value of the item is increasing by 8% each year.

A population of mutant venus fly trap plants are taking over an island in the South Pacific, capturing everything from insects to small rodents. When they were first discovered they covered 4 square kilometers. As the population grows, the plants spread and cover more land. Use the table to write an equation.

• y=4(4)^x

• y=4(2.68)^x

• y=4(1+1.67)^x

• y=4(1.67)^x