Unit 4B: Writing and Solving Exponentials

Suppose a culture of bacteria begins with 5000 cells and dies by 30% each year. Write an equation that represents this situation.

• y=5000(0.7)^x

• y=30(5000)^x

• y=5000(1.3)^x

• y=5000(30)^x

Write the equation that represents the table below:

• y=½(4)^x
• y=2(4)^x
• y=4(2)^x
• y=4(½)^x

Tags

CCSS.HSF.LE.A.2

You buy a new computer for $2100. The computer decreases by 50% annually. This is modeled by the equation

f(x) = 2100(.5)^x

How much is it worth after 2 years?

• $225

• $325

• $425

• $525

Solve: 7^x = 49

• x = 1

• x = 2

• x = 7

Write an explicit rule for the sequence below.

5, 15, 45, . . .

• a_n = a_n-1 x 3

• a_n = 5(3)^n-1

• a_n = 3(5)^n-1

• a_n = 5 + (n-1)3

What is the common ratio for the sequence below?

3, 15, 75...

• 12

• 1/5

• 5

The population of Winnemucca, Nevada can be modeled by P(x) = 6191(1.04)^t where t is the number of years since 1990. What was the population ten years later?

• 0 people

• 6,191 people

• 9,164 people

• 179,078 people