Sample Methods and Exponential Functions

The number of bacteria in a culture grows exponentially. It can be modeled with the function f (x) = 20 × 2^x, which is found on the graph. How many more bacteria will there be after six hours?

• 1200

• 1000

• 960

• 1280

Tags

CCSS.HSF-LE.A.1A

Which table shows exponential growth?

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Tags

CCSS.HSF-LE.A.1A

If y = ab^x represents an exponential decay function, what are the possible values of b?

• b = 1

• b > 1

• b < 0

• 0 < b < 1

Tags

CCSS.HSF-IF.C.8B

A phone originally costs $400. Its value after x years can be found using the equation y = 400(3/4)^x. What will the graph of the equation look like?

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Tags

CCSS.HSF-IF.C.7E

Consider the function given by the equation y = 0.25(2.3) ^x. What is the range of the function?

• y < 0

• y ≤ 0

• y > 0

• y ≥ 0

Alexandra and Diana love to collect business cards from local businesses. Alexandra starts the year with 10 cards and collects 20 more per month. Diana has 3 cards at the beginning of the year and doubles the number every month. The graph shows the total amount of cards that they have. The 0 on the Months axis represents January. In which month will Diana have more cards than Alexandra for the first time?

• July

• April

• May

• June

Stephanie and Cooley are learning Russian. Currently they each know 200 words. Stephanie plans to learn 10 new words per day. Cooley plans to use a special method that allows her to increase the number of words she knows by 4% per day. The graph shows the plans. After approximately how many days will Stephanie and Cooley know the same number of words?

• 13

• 6

• 11

• 12

• 3

Kaelyn invests $5000 in a savings account that pays 4% interest compounded annually. What is an expression for the amount of money that Kaelyn will have in her savings account in five years?

• $5000 ⋅ 1.4⁵

• $5000 + 0.04⁵

• $5000 ⋅ 1.04⁵

• $5000 + 1.04⁵

Tags

CCSS.HSF.BF.A.2