point-slope form

Point-Slope Point-Slope FormForm

What we Know so far….What we Know so far….

Slope Intercept Form

bmxy

Where m is the slope and b is the intercept

What we Know so far….What we Know so far….Slope

12

12

xxyy

xy

runrisem

Where two points are given as (x1,y1) and (x2,y2)

The New Stuff… Write The New Stuff… Write equations equations

Slope-intercept form is:

bmxy

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 + 8Easy if I know the y-intercept… but if I don’t?

The New Stuff… Point- Slope The New Stuff… Point- Slope FormFormPoint- Slope form is:

)( 11 xxmyy Where m is the slope

and (x1,y1) is the given point that the line goes through

The New Stuff… Point- Slope The New Stuff… Point- Slope FormFormPoint- Slope form is:

)( 11 xxmyy Where does this equation come from?

mxxyy

12

12

Using Point-Slope Form to Using Point-Slope Form to graphgraph

1 2 43

5

-1-2-3-4-51234

5-1-2-3-4-5

)( 11 xxmyy

)2(253 xy

Point is (2,3)

Slope is 25

Manipulate Point-Slope Manipulate Point-Slope Form to Slope-Intercept Form to Slope-Intercept

formform)2(

253 xy

Simplify5

253 xy

225

xy

Using Point-Slope Form to Using Point-Slope Form to graphgraph

1 2 43

5

-1-2-3-4-51234

5-1-2-3-4-5

)( 11 xxmyy

)4(23 xy

Point is (4,-3)

Slope is 12

Manipulate Point-Slope Manipulate Point-Slope Form to Slope-Intercept Form to Slope-Intercept

formform

823 xy

52 xy

)4(23 xy

Your turnYour turn)1(

311 xy

)3(252 xy

)1(413 xy

HomeworkHomework

Pg. 304 #2 to 8 evenPg. 304 #2 to 8 evenWrite slope and pointWrite slope and point

Plot graphPlot graphWrite equation in slope Write equation in slope

intercept formintercept form