Today’s Agenda

• Attendance / Announcements– Exam 1 – Tuesday 9/24• Covers Chapters 1.1 to 2.4 (skip 2.5)

• Project 1• Questions from HW?• Section 2.2b, 2.3

Quick ReviewWrite the following equation in slope-

intercept form752 yx

Slopes…continuedFind the slope of the

line through the points (-4, 2) and (3,

2)

So, horizontal lines have a slope of….

And have an equation of….

Slopes…continuedFind the slope of the

line through the points (-3, 2) and (-

3, 6)

So, vertical lines have a slope of….

And have an equation of….

Slopes…continuedParallel lines never

intersect. They have the same slope.

Slopes…continuedAre the following pairs of lines parallel?

6

4

32

32

xy

xy

6

6

xy

xy

843

643

yx

xy

Slopes…continuedPerpendicular lines

meet at right angles. They have slopes of negative

reciprocals.

Also, the product of the slopes of perpendicular lines must equal -1

Slopes…continuedAre the following pairs of lines parallel,

perpendicular, or neither?

3

4

xy

xy

Slopes…continuedAre the following pairs of lines parallel,

perpendicular, or neither?

3

6

61

xy

y

41

23

32 4

xy

xy

Point-Slope Form (p. 94)To find an equation of a line

when you have a point, and a slope

Point-Slope Form Find the equation of the line with slope -3 through the point (-4, 1)

)( 11 xxmyy

Point-Slope Form Find the equation of the line that passes through the points (-1, -2)

and (2, -1))( 11 xxmyy

Forms of Linear Equations (p. 95)

2.3 Linear Modeling

General Idea / Steps

• Plot data onto a graph (scatterplot)

• Create “line of best fit” (linear model)

• Find equation of linear model

• Use to predict new or unknown data

Year 2003 2004 2005 2006 2007Profit 15.0 16.6 16.4 20.8 22.2

The profits of the General Electric Company (GE), in billions of dollars, over a five-year period are shown in the following table.Let x = 3 correspond to 2003. Plot the data.

Year 2003 2004 2005 2006 2007Profit 15.0 16.6 16.4 20.8 22.2

What would you expect the profit to be in 2010?

Remember, the x-value corresponds to the year. And the y-value corresponds to the profit.

Year 2003 2004 2005 2006 2007Profit 15.0 16.6 16.4 20.8 22.2

When would you expect the profit to exceed $50 billion?

Remember, the x-value corresponds to the year. And the y-value corresponds to the profit.

Classwork / Homework

Page 97 33 – 61 e.o.odd, 69

Page 108 1, 5, 7

Reviewing Lines Worksheet