Algebra 2 Schedule: Class Announcements Wednesday Warm-Up Homework Check/Questions 2.2 Notes Begin...

Algebra 2Algebra 2

Schedule:• Class Announcements• Wednesday Warm-Up• Homework Check/Questions• 2.2 Notes• Begin Homework

Wednesday Warm-UpWednesday Warm-Up

1) What is the greatest common factor of 42, 126, and 210 ?

A. 2

B. 6

C. 14

D. 21

E. 42

2) Sales for a business were 3 million dollars more the second year than the first, and sales for the third year were double the sales for the second year. If sales for the third year were 38 million dollars, what were sales, in millions of dollars, for the first year?

A. 16

B. 17.5

C. 20.5

D. 22

E. 35

2.2 – Slope and Rate of Change

Objectives:1. Find the slope of lines.2. Classify lines based on slope.3. Use slopes in real life. 

Vocabulary: slope

Algebra 2Algebra 2

Classify slopes:positive slopesnegative slopes

horizontal line slope = 0vertical line no slope

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steepness = magnitude of slope

direction = sign of slopem = -2

steepness

direction

“READ” SLOPES FROM LEFT TO

RIGHT!

Important:

Using Slopes

riserun___ =

Vertical change

Horizontal change_________

Estimate the slope of the line.

Meet Slope Man…Meet Slope Man…

-+

u

0

12

12

xxyy

ΔxΔy

slope

How do I find slope?1.Pick/label points &

use formula.2.Simplify.

Find the slope of:M(-4, 5) and N(3, 15)

710

m

rise – vertical change

run – horizontal change

Rising or falling? Steep or

level?

12

12

xxyy

ΔxΔy

slope

How do I find slope?1.Pick/label points &

use formula.2.Simplify.

Find the slope of:P(0, -5) and N(4, -7)

rise – vertical change

run – horizontal change

2 1-

4 2-

m

Rising or falling? Steep or

level?

12

12

xxyy

ΔxΔy

slope

How do I find slope?1.Pick/label points &

use formula.2.Simplify.

Find the slope of:A(4, 16) and B(12, -8)

rise – vertical change

run – horizontal change

-3824-

m

Rising or falling? Steep or

level?

Parallel Lines:same slopes m1 = m2

Perpendicular Lines:opposite reciprocal slopes

Classify these lines based on their slopes:

21 m

1m

32

m,32

m 21

23

m,32

m 21

1 2

2 3m , m

3 2

32

m,32

m 21

parallel

neither

perp.

neither

Parallel Lines:same slopes m1 = m2

Perpendicular Lines:opposite reciprocal slopes

Classify these lines based on their slopes:

A(5, 7), B(10, 12) and C(3, -2), D(5, 0)

E(3, 6), F(1, 2) and G(4, 1), H(0, 3)

21 m

1m

parallel

perp.

In 1993 there were 16 million cell phones. In 1996 there were 44 million. What is the rate of change? 9.3 million phones per

yearAt this rate, how many cell phones can we predict there to be today?

Is this reasonable to believe?

192.7 million phones

Mobile Phones

Find the slope of a slide that drops 8’ over a distance of 24’.

You decide to make “The Slide of Death.” If you have the slide drop 54’ over 80’, what is the slope of the “The Slide of Death?”

31

m

4027

m

Homework:• pgs. 79-80 #18, 19, 23-25, 41, 42, 44

• 2.1-2.3 Quiz on Monday, September 17th

Algebra 2Algebra 2