2. Welcome! September 20, 2010 Do Now: Do Now Do work in your Notes When you are done writing, put your pencil down and silently look up. Agenda: I.Do Now II.HW Check III.Intro to Slope Formula IV.Modeling Problem V.Work on class activity VI.Ticket to Go Take out: Pencil & journal Homework: Objectives: Students will determine the relationship between points and slope Students will explore how scale changes a graph Students will discover how to write the equation for a line

3. Essential Topics Skills (SWBAT) Homework Monday  Qualities of Linear Relationships  Students identify Linear vs. Nonlinear  Students will Find conditions of Linear Relationships  Students identify Increasing and Decreasing Linear Relationships Pg.14; PS G & H Tuesday (Double Block)  Qualities of Linear Relationships  Identifying Linea Tables & Equations  Students identify Increasing and Decreasing Linear Relationships  Interpret word problems focusing on Direct Variation and increasing and decreasing linear functions Pg. 16; #1 Wednesday (Split Double Block)  What is Slope?  How is slope related to Rate of Change?  How is Slope used to describe a Linear Relationship?  How do we find slopes of lines?  define slope in the context of linear relationships  use rise/run method and slope formula to find slope of lines  -identify 0 and undefined slope Pg. 20; #8-10 Thursday  How is slope related to increasing and decreasing lines?  How is slope interpreted in a Linear Relationship Word Problem?  Find slopes of increasing and decreasing lines  Describe the slope and it’s effect within word problems No HW Friday  Direct Variation  Directly Proportional Relationships  Take Quiz on increasing and decreasing rates  -Find Direct Variation by looking at Graphs and Tables  -Find Algebraic Equations to represent linear relationships thru words, graphs, and tables Pg.27-28; PS C Pg.29; Explore

4. Assuming each line is one unit, how many ways can we find the slope of this line? (-2, -2) (4, 1)

5. Could these two lines have the same slope? How? Complete in pairs p30, psD #1 (10 minutes)

6. Graph and find the slope given the points 1. (-3, 4) and (-7, 2) 2. (2, 4) and (3, 3) 3. (3, 5) and (4, 5)4. (-3, 4) and (-4, 6) 1.Two of the lines have negative slope, what do you notice about these lines? 2.One of the lines has a slope of 0. What do you notice about that line? IS THERE A BETTER WAY TO FIND SLOPE???

7. FORMULA FOR FINDING SLOPE The formula is used when you know two points of a line. EXAMPLE

8. Find the slope of the line between the two points (-4, 8) and (10, -4) If it helps label the points. Then use the formula

9. Vocabulary The equation for a line is often written in the form: y = mx + b, where m = slope and b = y-intercept. This is called Slope-Intercept form. Coefficient – The multiplier of a variable – Example: y = 2x + 3, 2 is the coefficient of x y-intercept – The y-coordinate of the point at which the line crosses (or intercepts) the y-axis – What is the y-intercept for y = 2x + 3? – How about y = 3x - 4? How do you know?

10. Write the Equation If a line has a slope of 3 and passes through the point (2, 5). Since slope = 3, we can replace m in y=mx+b with y=3x+b Now, replace x and y with 2 and 5, respectively giving you 5=3(2) + b Simplify, and you get b = -1 So, the equation for the line is: y = 3x -1

11. Find the line using the given Slope 4 and passes through (1, 5) Slope -2 and passes through (8, -12) Slope 0 and passes through (3, 5) If you finish early, graph each equation.

12. Here’s a Challenge! How could you find the equation for a line using just two points? Try with the following points (3, 7) and (8, 12) (6, 11) and (18, 17) (0, 0) and (100, 100) (3, 5) and (-1, 5)

13. Ticket to GO! Find the equation for the line with slope 2/3 that passes through the point (9, 9)