Exponential Functions CFA Re-test

Which statement is true about g(x) = -5(4)^x.

• The domain is all real numbers greater than or equal to -5.

• The range is all real numbers.

• The domain is all real number less than or equal to 0.

• The range is all real numbers less than or equal to zero.

• The growth factor of the amount of interest earned.

• The number of years.

• The starting balance

• The decay factor of the amount of interest earned.

Researchers studied a population of insects over time. There are 1600 insects initially. After the first year there were 2,400 insects. If the population of the insects continues to grow at this rate every year, which function can be used to model the population x years after the researchers began their study?

The value of a car is $15,000 and depreciates at a rate of 8% per year. What is the exponential equation?

• y=8(15,000)^x
• y=15,000(1.08)^x
• y=15,000(0.92)^x
• y=15,000(0.08)^x

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

An adult takes 800 mg of ibuprofen. Each hour, the amount of ibuprofen in the person’s system decreases by about 29%. Create a function that can be used to find y, the amount of ibuprofen remaining after x hours.

Mathematical Equivalence

ON

• y
• 0
• x
• 1/2
• 5
• 2.5

• The initial balance in the account decreases at a rate of 97.5% each year.

• The balance in the account increases at a rate of 102.5% each year.

• The initial balance in the account was $850.

• The balance in the account at the end of 1 year is $850.

• The y-intercept is

  (0, 35),

• The x-intercept is

  (0.20, 0).

• The graph of the function is increasing for all values of x.

• The asymptote of the function is y = 0.20.

Which graph matches this equation?

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