Page 850 - Algebra 1

Example
5
Application: Ticket Prices
At an amusement park, children under three years of age are free.
Ages 3 to 12 pay $20. Everyone older than 12 pays $30. Write the function that represents this information, and graph the function.
SOLUTION
First, identify the intervals for the independent variables. Let x represent age in years.
under three ages 3 to 12 older than 12
x < 3
3 ≤ x ≤ 12 x > 12
Then, write the function rule. f(x) is the price of the ticket.
⎧ 0 i f x < 3 f(x)=⎨20 if 3≤x≤12
⎩30 ifx>12 Graph the function.
30 20
Evaluate each step function for the values given.
10
O
x
5
1
0
15
Lesson Practice
(Ex 1)
a. f(x) = ⎨⎧-2 if x ≤ 1 for x = -3 and x = 10.
⎩4 if x > 1
b. f(x)=⎧⎨6 if x<9forx=8andx=9.
⎩-11 ifx≥9
Evaluate each piecewise function for the values given.
(Ex 2)
c. f(x)=⎧⎨2x3 if x<0forx=4andx=-1.
⎩10-3x ifx≥0
d. f(x) = ⎨⎧3x if x ≤ - 1 for x = -5 and x = 1.
⎩x-5 ifx>-1 Graph each step function.
(Ex 3)
e.f(x)=⎨⎧7 ifx<5
⎩2 ifx≥5
⎧ 3 i f x < - 3
f. f(x)=⎨0 if -3≤x<3
⎩ -3 ifx≥3
y
Appendix Lesson 2 835
APPENDIX LESSONS