Transcript Slope form is - aianjack.com

Point-Slope Form
What we Know so far….
Slope Intercept Form
y  m x b
Where m is the slope and b
is the intercept
What we Know so far….
Slope
rise y y2  y1
m


run x x2  x1
Where two points are
given as (x1,y1) and (x2,y2)
The New Stuff… Write equations
Slope-intercept form is:
y  m x b
Where m is the slope and b is the
y-intercept
Example: Find the equation of the line with
slope -2 and y-intercept 8
y = -2x + 8
Easy if I know the y-intercept… but if I don’t?
The New Stuff… Point- Slope Form
Point- Slope form is:
y  y1  m( x  x1 )
Where m is the slope
and (x1,y1) is the
given point that the
line goes through
The New Stuff… Point- Slope Form
Point- Slope form is:
y  y1  m( x  x1 )
Where does this equation come from?
y2  y1
m
x2  x1
Using Point-Slope Form to graph
5
5
y  3  ( x  2)
4
2
3
2
y

y

m
(
x

x
)
1
1
1
-5
-4 -3 -2 -1
1 2 3
-1
-2
-3
-4
-5
4
5
Slope is 5
2
Point is (2,3)
Manipulate Point-Slope Form to
Slope-Intercept form
5
y  3  ( x  2)
2
5
y 3  x5
Simplify
2
5
y  x2
2
Using Point-Slope Form to graph
y  3  2( x  4)
5
4
3
2
1
-5
-4 -3 -2 -1
y  y1  m( x  x1 )
1 2 3
-1
-2
-3
-4
-5
4
5
Slope is  2
1
Point is (4,-3)
Manipulate Point-Slope Form to
Slope-Intercept form
y  3  2( x  4)
y  3  2 x  8
y  2 x  5
Your turn
1
y  1  ( x  1)
3
5
y  2  ( x  3)
2
1
y  3   ( x  1)
4
Homework
Pg. 304 #2 to 8 even
Write slope and point
Plot graph
Write equation in slope
intercept form