2. SWBAT… Write lines in slope-intercept form 1/7/09 Agenda 1.WU (5 min) 2.Notes on slope intercept Warm Up What is the slope of the line passing through (-5, 2) and (6, 7) in the standard (x, y) coordinate plane? HW #2: Writing Equations in slope-intercept

3. Find the rate of change. Explain what the rate of change means.

4. When an equation is in slope-intercept form: What is the slope? ____________ Now look at the equation below…… What is the y-intercept? ____________

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

6. Converting linear equations into Slope- Intercept Form

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

8. Class example - convert Into Slope-Intercept Form (divide both sides by 2 to get y alone) (now simplify all fractions) 21

9. *** Your turn - example 1 *** 5y = 10x + 15 Convert to Slope-Intercept Form: (divide both sides by 5 to get y alone) (now simplify all fractions) y = 2x + 3 BRAVO!!

10. *** 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 intercept? ____________

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

12. *** Class example *** 21x – 7y =14 Convert to Slope-Intercept Form: (subtract both sides by 21x) -7y = -21x + 14 (now divide both sides by -7) y = 3x – 2 (simplify all fractions)

13. 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 *** Final Example - Your turn – example 3-Convert to Slope-Intercept Form *** What is the slope? ____________ What is the intercept? ____________

14. 2y + 26 = -6x (subtract both sides by 26) 2y = -6x - 26 (now divide both sides by 2 y = -3x - 13 (simplify all fractions) You are a math wizard! *** Check Your Answer ***

15. Four students are renting a car for a road trip. The cost of renting the car is given by the function C = 12.5 + 21d, where C is the total cost for renting the car for d days. What does the slope of the function represent? 1.number of people 2.cost per day 3.number of days 4.miles per gallon

16. The cost of prints from an online photo processor is given by C(p) = 29.99 + 0.13p. $29.99 is the cost of membership, and p is the number of 4-inch by 6-inch prints. What does the slope represent? 1.cost per print 2.cost of the membership 3.cost of the membership and 1 print 4.number of prints