Page 746 - Algebra 1

Caution
The variable y represents millions of people. The table entry y1 = 12.413 means 12.413 million.
SOLUTION Enter the function rule into the Y= editor. Access the Table
function by pressing . Since 2005 is 5 years after 2000, find the y-value for x = 5. The population was about 12,413,000. To find when the population will reach 13 million, scroll down until y equals 13 or more. It occurs during the 27th year after 2000, or 2027.
Lesson Practice
Evaluate each function for the given values.
(Ex 1)
a. Evaluate f(x) = 2x for x = -4, 0, and 5.
b. Evaluate f(x) = -3(3)x for x = -3, 1, and 3.
Determine whether each set of ordered pairs satisfies an exponential function.
Explain your answer.
(Ex 2)
c. {(3, -12), (6, -24), (12, -48), (9, -36)} d. {(3, 108), (1, 12), (2, 36), (4, 324)}
Graph each function by making a table of ordered pairs.
Practice
Distributed and Integrated
(Ex 3) x
(Ex 4)
(Ex 4)
j.
(Ex 5)
3
_1 e. y = 2(3)x f. y = -4(2)x g. y = 2(4)
Using a graphing calculator, graph each pair of functions on the same screen. Tell how the graphs are alike and how they are different.
h.
_1 x _1 x y = ( ) and y = -( )
3
_1 x and y = -2( )
The exponential function y = 8.05(1.01683)x models the approximate population of North Carolina from 2000 to 2006, where x is the number of years after 2000 and y represents millions of people. Use a graphing calculator to find the approximate population of North Carolina
in 2006. Assuming the model does not change, when will the population reach 10 million?
3
i. y = -2(3)
*1. Evaluate the function f(x) = 2(5)x for x = -2, 0, and 2. (108)
2. Graph the function f (x) = ⎢x - 2⎢. (107)
x
Lesson 108 731