# AU6 ```Name: ______________________
Class: __________________
AU6 – Exponents & Exponential Review
Total: 54 pts
Multiple Choice
Circle the choice that best completes the statement or answers the question. (2 pts each)
1. What is the value of 4 2  4 0 ?
a) 0
b) 1
c)
1
16
d) 1
1
16
2. Write the following using the appropriate unit in prefix form.
2.8  10 3 meters
a) 2.8 centimeters
b) 0.28 millimeters
c) 2.8 kilometers
d) 2800 kilometers
c) 9 7
d) 3 7
3. The expression 33  3 4 is equivalent to
a) 9 12
b) 312



4. Which expression represents 3x 2 y 4 4 xy2 in simplest form?
a) 12 x 2 y 8
b) 12 x 2 y 6
c) 12 x 3 y 8
d) 12 x 3 y 6
c) 27x 5
d) 27x 6
5. The expression (3x 2 ) 3 is equivalent to
a) 9x 5
b) 9x 6
3x 6 x  in simplest form?
2
4
6. Which expression represents
a) 9x
9x
b) 2x
c) x 9
d) 2x 3
c) 6 3  3 2
d) 3 2  36
7. The expression 9 3  2 3 is equivalent to
a) 3 6  2 3
b) 6 3  2 3
1
8. What is the approximate solution to the given system?
 f x   2 x

 g x   4 x  10
a) 1.69, 3.23
b) 1.67, 3.33
d) 3.23, 1.69
c) No solution
9. Which of the following functions model an exponential decay?
a) f x   x  4
b) g x   2  4
c) h( x)  x
x
1
d) j x   2   
4
2
x
10. Which equation best represents the data in the accompanying table?
1
a) y 
3
x
y
1
3
2
9
3
27
4
81
x
b) y  3 x
d) y  x 3
c) y  3 x
11. Kathy plans to purchase a car that depreciates (loses value) at a rate of 14% per year. The
initial cost of the car is \$21,000. Which equation represents the value, v of the car after 3
years?
a) v  210000.14
3
b) v  210000.86
3
c) v  210001.14 
5,
-25, 125, -625, …
a) The sequence is not geometric and the common ratio is -5.
b) The sequence is arithmetic and the common difference is -5.
c) The sequence is geometric and the common ratio is 5.
d) The sequence is geometric and the common ratio is -5.
2
3
d) v  210001.86 
3
13. Find the product of 2.5  10 5 and 4  10 3 . Leave your answer in scientific notation. (2pts)
14. Evaluate the expression 4 x 3 y for x  2 and y  5 .
15. Simplify the following:
3.6  10 7
3  10 3
16. Suppose a population of 150 mice triples in size every 4 months.
How many mice will there be after 3 years?
3
(2pts)
(2pts)
(2pts)
17. The inside diameter of a certain size of ring is 1.732  10 2 meter. Is it more appropriate to
report the ring diameter as 1.732  10 2 meter or 17.32 millimeters? Explain.
(2pts)
________________________________________________________________________
________________________________________________________________________
18. Is the statement 0.25  4 1 true or false? Explain your reasoning.
(2pts)
________________________________________________________________________
________________________________________________________________________
19. The population of the District of Columbia (D.C.) is about 5.9  10 5 .
South Dakota has a population of approximately 8  10 5 .
a. Find the total of the populations. Leave your answer in scientific notation.
b. How many more people live in South Dakota than in D.C.?
4
(2pts)
20. If a new car cost \$25,000 and the rate of depreciation is 8% per year.
(3pts)
a. Write an equation that models the cost of a new car.
b. Use your equation to determine what the value of the car is after 60 months, round to
the nearest cent.
21. Chain emails are emails with a message suggesting you will have good luck if you forward
the email on to others. Suppose a student started a chain email by sending the message to 3
friends and asking those friends to each send the same email to 3 more friends exactly 1 day
(3pts)
a. Write an explicit formula for the sequence that models the number of people who will
receive the email on the nth day. (Let the first day be the day the original email was sent.)
Assume everyone who receives the email follows the directions.
b. Which day will be the first day that the number of people receiving the email exceeds
100?
5
22. On the set of axes below, solve the following system of equations graphically for all values
of x and y.
(4 pts)
 y  0.5  4 x

 y  60 x  112
y
x
6
23.
Population of Smallville
Year
Population in
thousands
(6 pts)
2007
2008
2009
2010 2011
2012
15
17.6
22.2
28.7
49.3
37.1
a. Use the statistical features of your calculator to construct a scatter plot and fit an
appropriate function to the data. Justify using the correlation coefficient.
b. From your table, calculate the average rate of change in total number of sightings for
each of the following time intervals.
a. 2007–2009
b. 2009–2011
c. How do the average rates of change help to support your argument of whether a linear
or exponential model is better suited for the data?
7
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