GRAPHING LINEAR EQUATIONS AND

FUNCTIONS

Carly Cofer

4 .1 : THE CARTESIAN COORIDINATE SYSTEM

X ~ Axis

Y ~ Axis

Origin

QUADRANTS

Quadrant II

(-,+)

Quadrant I

(+,+)

Quadrant IV(+,-)

Quadrant III(-,-)

Every point is written in the form

( X , Y )

To plot the point, begin at the

origin

Move horizontally along the X ~

Axis to the designated X coordinate

Than move vertically along the line

of the X coordinate to the

designated Y coordinate

( 4 , -3 )

TO PLOT A POINT…

( -6 , 3 )

( -9 , -2 )

( 5 , -2 )

( 7 , 4 )

( 0 , 8 )

( -10 , 0 )

LETS TRY IT OUT!

Without plotting the

points, can you figure

out what quadrant these

points lie in? :• ( -7 , -5 )• ( 8 , 1 )• ( -9 , 4 )• ( 6 , -3 )

LETS TRY IT OUT!

Quadrant II

(-,+)

Quadrant I

(+,+)Quadran

t

III(-,-)

Quadrant IV(+,-)

SCATTER PLOTS

A Scatter Plot is a specific type of graph which has

multiple sets of coordinate pairs

These pairs of points are typically organized in a

data table

Each pair is plotted on the same graph

This type of graph is often used to interpret data

and trends in real world applications

SCATTER PLOTSSca

tter

Plot

Data Table

X -8 -4 -6 1 -4 5 3

Y 5 2 -7 8 -9 -3 6

REAL WORLD EXAMPLE

Number of teens with cell phones

Create a scatter graph for the data table

10009008007006005004003002001000 13 14 15 16 17 18 19 20

21 22

X 13 14 15 16 17 18 19

Y 245

297

356

417

584

532

672

REAL WORLD EXAMPLECell phone scatter graph

10009008007006005004003002001000 13 14 15 16 17 18 19 20

21 22

Interpretation of the data :• 1~ At what age do the greatest

amount of teens have cell phones?• 2~ At what age do the least

amount of teens have cell phones?• 3~ How many 14 year olds have

cell phones?• 4~ What is the greatest amount

of cell phone carrying teens at any age?

• 5~ What is the least amount of cell phone carrying teens at any age?

• 6~ About how many 17.5 year olds have cell phones?

X 13 14 15 16 17 18 19

Y 245

297

356

417

584

532

672

Lets try a real world example of our

own!

Cell phone service providers

Interpretation of the data :• 1~ What provider(s) is used by

the greatest amount of students?• 2~ What provider(s) is used by

the least amount of students?• 3~ How many students use

Verizon?• 4~ What is the greatest amount of

students using the same provider?• 5~ What is the least amount of

students using the same provider?

LETS TRY IT OUT!

X AT&T Verizon

T Mobil

e

Metro PCS

Cricket

Sprint Other

Y

A V T M C S O

109876543210

Page 206• 3, 4, 5, 6, 7 & 8

IN CLASS EXERCISES

ON THE CALCULATOR

2nd Y = [STAT

PLOT]• 1 : Plot1…On• Make sure Plot1 is in the on

position

GRAPH

STAT• 1 : Edit

• For L1, enter in the X values

• For L2, enter in the Y values

WINDOW• Adjust values for

• Xmin,• Xmax• Xscale• Ymin• Ymax • Yscale

Page 206

10, 12, 16, 18, 20, 22, 24 & 25

Good Luck!

TRY IT YOURSELF!

"Coordinate Grids." Chart. ClipArt ETC. First Last. Web.

23 Oct 2011.

<http://etc.usf.edu/clipart/galleries/math/coordinate_grids

>.

Larson, Ron on, Laurie Laurie Boswell, and Timothy

Timothy D. Kanold. Algebra 1. McDougal

Littell/Houghton Mifflin, 2006. 202~209. Print.

WORKS CITED