Transcript Chapter 4 - cloudfront.net

Chapter 4
4.6 Slope Intercept Form
Objectives


Write a linear equation in slope-intercept form.
Graph a line using slope-intercept form.
Slope intercept form


You have seen that you can graph a line if you know two
points on the line. Another way is to use the slope of the
line and the point that contains the y-intercept.
This is y= mx+b also known as the slope intercept form
Example#1
Graph the line given the slope and y-intercept.
Slope = -2/5 and y = 4

Example #2
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
Graph the line given the slope and y-intercept.
slope = 2, y-intercept = –3
Student guided practice

Do problems 1-4 in your book pg.272
Sloe-intercept form

you know the slope of a line and the y-intercept, you can
write an equation that describes the line.
Example #3

If a line has a slope of 2 and the y-intercept is 3.Write the
slope intercept form of the line.
Example#4


Write the equation that describes the line in
slope-intercept form.
slope =1/4 ; y-intercept = 4
Example


Write the equation that describes the line in
slope-intercept form.
slope = –9; y-intercept = 5/4
Student guided practice

Do problems 6 and 7 in your book page 272
Example

Write the equation that describes the line in
slope-intercept form.
Example


Write the equation that describes the line in
slope-intercept form.
slope = 2; (3, 4) is on the line.
Example



Write the equation in slope-intercept form.Then
graph the line described by the equation.
A)y = 3x – 1
B) 2y + 3x = 6
Example


Write the equation in slope-intercept form.Then
graph the line described by the equation.
Y=-4
Student guided practice

Do problems 10 to 12 in your book page 272
Application

A closet organizer charges a $100 initial
consultation fee plus $30 per hour.The cost as a
function of the number of hours worked is
graphed below.
Application


a. Write an equation that represents the cost as a
function of the number of hours.
Solution
Cost
is
$30
y
=
30
for each
hour
•x
An equation is y = 30x + 100.
plus
$100
+
100
Application


A caterer charges a $200 fee plus $18 per person
served.The cost as a function of the number of
guests is shown in the graph.
. Write an equation that represents the cost as a
function of the number of guests.
Homework

Do problems 14-20 in your book page 272
Closure


Today we learned about the slope intercept form
Next class we are going to learned about point-slope
form.