Copyright © by Holt, Rinehart and Winston. 30 Holt Algebra 1All rights reserved.

Name Date Class

ReteachLinear, Quadratic, and Exponential Models11-4

LESSON

Graph to decide whether data is best modeled by a linear, quadratic or exponential function.

Graph ! !2, 0 " , ! !1, !3 " , ! 0, !4 " , ! 1, !3 " , ! 2, 0 " . What kind of model best describes the data?

Graph each data set. Which kind of model best describes the data?

1. ! !2, !4 " , ! !1, !2 " , ! 0, 0 " , ! 1, 2 " , ! 2, 4 " 2. ! !1, 4 " , ! 0, 2 " , ! 1, 1 " , ! 2, 1 __ 2 " , ! 3, 1 __ 4 "

linear exponential

Look for a pattern in each data set to determine which kind of model best describes the data.

3. x y

0 6

1 12

2 24

3 48

4. x y

0 10

1 18

2 28

3 40

5. x y

3 4

6 !2

9 !8

12 !14

exponential quadratic linear

You can also look at patterns in data to determine the correct model.

Linear functions have constant 1st differences.

x y

2 5

4 2

6 !1

8 !4

Quadratic functions have constant 2nd differences.

x y

1 !8

2 !5

3 0

4 7

Exponential functions have a constant ratio.

x y

0 !2

1 !8

2 !32

3 !128

Connect the points.The data appear to be quadratic.

!3

!3

!3

"3

"5

"7

"2

"2

#4

#4

#4

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12.03 Notes - compare functions

Copyright © by Holt, Rinehart and Winston. 34 Holt Algebra 1All rights reserved.

Name Date Class

LESSON

Use the table below to help you learn the characteristics of each data model and how to tell them apart.

Model Linear Quadratic Exponential

Pattern(y-values)

constant first differences

constant second differences

constant ratios

Graph

Equation y ! mx " b y ! ax 2 " bx " c y ! a b x

Identify each of the following as linear, quadratic, or exponential.

1. y ! 6 ! 2 " x 2. y ! 4x " 6 3. y ! 2 x 2 " 5x " 3

exponential linear quadratic

4. 5. 6.

quadratic exponential linear

7. 8. 9.

linear quadratic exponential

11-4Reading StrategiesUse a Table

x 5 4 3 2 1

y 128 64 32 16 8x #6 #7 #8 #9 #10

y 17 20 23 26 29

x 1 3 5 7 9

y 4 12 28 52 84

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