Exponential Functions Review

Given the function f(x) = 2x - 5, what is the value of f(2)?

• -1

• 9

• 1

• -9

Write an exponential function to represent the growth of a population of bacteria, given an initial population of 1000 and a growth rate of 20% per hour.

• P(t) = 1000 * (1 + 0.50)^t

• P(t) = 1000 * (1 + 0.20)^t

• P(t) = 1000 * (1 - 0.20)^t

• P(t) = 1000 * (1 + 0.10)^t

Identify the key features of the exponential function f(x) = 1(3)^x.

• Continuous decay

• y-intercept at (0,0)

• Continuous growth, y-intercept at (0,1), and growth factor 3

• x-intercept at (0,1)

A certain investment grows by 8% annually. Write an exponential function to represent the value of the investment after x years, if the initial investment is $5000.

• V(x) = 5000 * (1 + 0.8)^x

• V(x) = 5000 * (1 - 0.08)^x

• V(x) = 5000 * (1 + 0.08)^x

• V(x) = 5000 * (1 - 0.8)^x

A radioactive substance decays at a rate of 10% per hour. Write an exponential function to represent the amount of the substance remaining after x hours, if the initial amount is 500 grams.

• A(x) = 500 * (0.8)^x

• A(x) = 500 * (0.5)^x

• A(x) = 500 * (1.1)^x

• A(x) = 500 * (0.9)^x

Identify the key features of the exponential function g(x) = 0.5 * (1.5)^x.

• The key features are the exponent (x) and the constant (0.5).

• The key features are the slope (1.5) and the x-intercept (0.5).

• The key features are the coefficient (1.5) and the y-intercept (0.5).

• The key features are the base (1.5) and the initial value (0.5).

Write an exponential function given by the values on the table

• y = 2 * (4)^x

• y = 4 * (0.5)^x

• y = 3 * (2)^x

• y = 5 * (3)^x

Write the domain and range of the exponential function in inequalities

• Domain: x > 0, Range: y < 0
• Domain: x < 0, Range: y < 0
• Domain: x > 0, Range: y > 0

Given f(x) = -3(0.5)^x - 8, What is the value of f(4)?

• -11
• -8.18

• 8.18

• -5

Use your calculator to write the exponential regression equation and use it to predict the number of cells in the colony after 7 hours

• The number of cells will remain the same after 7 hours
• y = 14.75(2.74)^x , 17102

• y = 2.74(14.75)^x , 21589

• The number of cells cannot be predicted using exponential regression