Algebra 1

Chapter 5

Slope

RiseRun

Slope =

Slope is represented by the letter m

Where can slope be found in the world?

Construction

Recreation

Sports

Engineering

Quick Reminder

Lines rising from left to right have a positive slope

Lines falling from left to right have a negative slope

0 slope

No Slope= undefined

Finding Slope by counting squares

rise

run

Rise= 3

Run= 2

Slope=32

Practice

What is the slope?

Find the slope by counting rise over run.

Answer to practiceri

se

run

Slope= 31

or 3

More Practice

What is the slope? Count rise over run.

Answer

Slope=54-

Calculating slopeRequires two points (x ,y ) (x ,y )

m=

y - y x - x

2 1

2 1

2 21 1

Example

(3, -2)

(1, -4)

(x ,y )

(x ,y )1 1 2 2

(3 , -2)

(1 , -4)

y -y

x - x1

1

2

2

-4-11-3

-5-2

= =52

Slope Intercept Form

y= mx+bm= slope

b= y intercept

slope y intercept

y interceptThe y intercept is where the line crosses the

y axis. y axis

y intercept

y intercept = 2

x axis

y intercepty intercepts can be positive

or negative numbers

y axis

x axis

y axis

x axis

y intercept= +1

y intercept= -2

Graphing Slope Intercept FormStep one: graph y intercept on y axis

Step two: from that point use slope to graph second point

Step three: connect the points

You have now graphed a line using slope-intercept form.

Point-slope Form

y- y = m(x-x )1 1

Point slope form requirements

You must have one point and the slope of the line in order to write in point-slope form.

You then substitute the slope in for the letter m and the numbers from the point in there correct spot.

Prentice Hall Algebra I Volume 1 Teacher’s Edition Pearson Education Inc., 2011 (p.311).

Prentice Hall Algebra I Volume I Teacher’s Edition Teacher Resources Chapter 5, Pearson Education Inc., 2011 (Practice Forms)

This citation is for slides (8-28). I