Algebra Part 3
Unit 3
Name____________________________
Date________________
Warm-up
Find the slope of the line passing through the given points and describe the lines.
1. (4, 2) and (6, 8)
2. (-3, 0) and (2, -5)
3.
Guided Notes
Graph Using Slope-Intercept Form
Finding the Slope and y-Intercept of an Equation:
Words
An equation of a line written
in the form y = mx + b, is
called _____________________________
where m is the _____________and b is the
_________________ of the equation’s
graph.
Symbols
Graph
y = mx + b
slope y-intercept
y = 3x + 1
EXAMPLE:
Identify the slope and y-intercept of the line with the given equation.
a. y = 3x + 4
b. 3x + y = 2
Solution
a. Since the equation is in y = mx + b form, the slope of the line is ___________, and the
y-intercept is ________.
b. Rewrite the equation in slope-intercept form by solving for y.
 y = ___________________

the slope of the line is ______________, and the y-intercept is ___________________.
Practice
Identify the slope and y-intercept of the line with the given equation. If the equation is
not in slope-intercept form, put it in that form!!!
1.) y = 5x – 3
2.) 3x – 3y = 12
3.) 2x + y = 6
Slope:
Slope:
Slope:
Y-intercept:
Y-intercept:
Y-intercept:
Practice Graphing lines using slope and y-intercept:
For each example, plot the y-intercept and then make two more points using the slope of
the line.
1.) slope = ½ ; y-int = 4
2.) m = -1 ; y-int = -3
3.) m = 2 ; y-int = -1
Graph an equation using slope-intercept form
Graph the equation 2x + y = 3.
Solution
STEP 1
Rewrite the equation in slope intercept form.
y = _____________________
STEP 2
Identify the slope and the y-intercept.
m = ___________ and b = ______________
STEP 3
Plot the point that corresponds to the
y-intercept: ( _____, ______)
STEP 4
Use the slope to locate a second point on the line.
Draw a line through the two points.
y
Practice
Graph the equations. Write each equation in slope-intercept form first!!
1. y = -3x + 2
y-int =
2. y – 2x = 4
m=
3. y = x – 3
y-int =
y-int =
m=
4. y = -
m=
Homework: pgs. 247-248 #2, 3-6, 9, 11,15, 21-24
5
x+2
2
y-int =
m=