1. SWBAT… Write lines in slope-intercept form Monday, 1/11/09
Agenda
WU (5 min)
3 examples of slope as rate of change (10 min)
Cornell notes on “slope-intercept form” (30 min)
Warm-Up
1. Place “hw#1: Slope” in a pile on your desks
2. Complete vocabulary note card – “Slope”
3. Start problems on back of agenda
HW #2: Writing Equations in slope-intercept

2. WARM-UP – ON THE BACK OF AGENDA!!!
Frank had 5 gallons of gasoline in his bike.  After driving 100 miles, he had 3 gallons left. 
Find the slope of the line
What does this slope tell us?

3. Slope as the rate of change
a. Find the slope of the line
    Slope = rise/run = -2/100 = -1/50
   b.  What does this slope tell us?
Since -1/50 = -0.02, we know that Frank’s bike is burning 0.02 gallons of gasoline for every mile that he travels.   (The negative value of the slope tells us that the amount of gasoline in the tank is decreasing.)

4. Four students are renting a car for a road trip
Four students are renting a car for a road trip. The cost of renting the car is given by the function C = d, where C is the total cost for renting the car for d days. What does the slope of the function represent?
cost per day
Cost per day

5. The cost of prints from an online photo processor is given by C(p) = p. $29.99 is the cost of membership, and p is the number of 4-inch by 6-inch prints. What does the slope represent?
cost per print
cost of the membership
cost of the membership and 1 print
number of prints
Cost per print

6. Non-Linear Equations

7. Final study guide review
Monday, 1/4
Tuesday, 1/5
Wednesday, 1/6
Thursday, 1/7
Friday, 1/8
Get ready for Ch 4
Slope
½ Day: A
Monday, 1/11
Tuesday, 1/12
Wednesday, 1/13
Thursday, 1/14
Friday, 1/15
Writing equations of
lines in slope
intercept form (y=mx+b)
Graphing linear
functions using
y=mx+b
½ Day: B
y=mx+b (cont’d)
Writing equations
of lines in slope
intercept
form
Monday, 1/18
Tuesday, 1/19
Wednesday, 1/20
Thursday, 1/21
Friday, 1/22
MLK
NO CLASSES
form (cont’d)
Final study
guide review
Final study guide review
Monday, 1/25
Tuesday, 1/26
Wednesday, 1/27
Thursday, 1/28
Friday, 1/29
ALGEBRA FINAL
Point slope form &
Standard form
All 3 forms of lines
1. Slope-intercept
2. Point-slope
3. Standard
END OF Q2
END OF SEMESTER1

8. When an equation is in slope-intercept form:
y = mx + b
slope
y-intercept
Now look at the equation below…… 2
What is the slope? ____________ 1
What is the y-intercept? ____________

9. Given y = ½x + ¾, what is the slope and the y-intercept?
m = ½
b = ¾

10. Given y = ½x – ¾, what is the slope and the y-intercept?
m = ½
b = -¾

11. Given y = -½x – ¾, what is the slope and the y-intercept?
m = -½
b = -¾

12. 1. ) What is the slope. 10 2. ) What is the meaning of the slope. 3
1.) What is the slope? ) What is the meaning of the slope? 3.) What is the y-intercept. b = 5 4.) What is the meaning of the y-intercept? 5.) Write the equation of the line. y = .10x + 5
1.) Slope = 0.1
2.) The cell phone company charges $0.10 per minute
3.) (0, 5)
4.) The y-intercept is the flat fee of $5.00 per month.
5.) y = 0.1x + 5

13. y = mx + b y = mx+ b is an equation that defines a line
A line has two characteristics
Points that fall on the line
Slope

14. 1. ) What is the slope. 2. ) What is the meaning of the slope. 3
1.) What is the slope? 2.) What is the meaning of the slope? 3.) What is the y-intercept (write as an ordered pair) 4.) What is the meaning of the y-intercept? 5.) Write the equation of the line (y = mx + b).
1.) Slope = 0.1
2.) The cell phone company charges $0.10 per minute
3.) (0, 5)
4.) The y-intercept is the flat fee of $5.00 per month.
5.) y = 0.1x + 5

15. Converting linear equations into Slope-Intercept Form
4 Examples

16. Our main goal is to get the y alone on one side of the equation
Slope intercept form is:
y = mx + b
Our main goal is to get the y alone on one side of the equation

17. Example 1 - convert into Slope-Intercept Form
(divide both sides by 2 to get y alone)
(now simplify all fractions) 2 1
What is the slope? _____
What is the y-intercept? ______

18. *** Your turn – Example 2 – convert to Slope-Intercept Form ***
-3y = -9x – 12
Step 1: divide both sides by -3 to get y alone
Step 2: Simplify all fractions
Step 3: Write your equation in y = mx + b
What is the slope? ____________
What is the y-intercept? ____________

19. *** Check Your Answer ***
-3y = -9x – 12
(divide both sides by -3 to get y alone)
(now simplify all fractions)
-3y = -9x – 12
y = 3x + 4
Wow, you’re good at this!!
Slope = 3
Intercept = 4

20. ***Example 3*** Convert to Slope-Intercept Form
21x – 7y =14
(subtract both sides by 21x)
(now divide both sides by -7)
-7y = -21x + 14
(simplify all fractions)
y = 3x – 2
What is the slope? _________
What is the y-intercept? ________

21. EXIT SLIP Convert to Slope-Intercept Form ***
2y + 26 = -6x
Step 1: Subtract both sides by 26
Step 2: Divide both sides by 2 to get y by itself
Step 3: Simplify all fractions
What is the slope? ____________
What is the y-intercept? ____________

22. *** Check Your Answer ***
2y + 26 = -6x
(subtract both sides by 26)
(now divide both sides by 2
2y = -6x – 26
(simplify all fractions)
y = -3x – 13
You are a math wizard!

23. In the standard (x, y) coordinate plane, what is the slope of the line given by the equation 5x – 4y = 3?
y = -5/4x – ¾
m = -5/4