1. Warm-Up Evaluate for x = -1, 0, and 2. 1.f(x) = 3x – 7 2. f(x) = -2x + 12 5.1

2. Objectives: 1.Write linear equations given m and b. 2.Use linear equations in real life. Vocabulary: Slope-intercept Form Writing Linear Equations in Slope-Intercept Form 5.1

3. Slope-intercept Form: m = b = y = mx + b Writing Linear Equations in Slope-Intercept Form 5.1 slope of a line = y- intercept (0, b) rise run

4. Reviewing Chapter 4 Find the slope and y-intercept of these: y = 2x + 5 m = b =

5. Reviewing Chapter 4 Find the slope and y-intercept of these: y = -x – 3 m = b =

6. Reviewing Chapter 4 Find the slope and y-intercept of these: y = 4 m = b = What kind of line is this?

7. Reviewing Chapter 4 Find the slope and y-intercept of these: y = ½x + 4 m = b =

8. Reviewing Chapter 4 Find the slope and y-intercept of these: y = 3 – 7x m = b =

9. y = mx + b Writing Linear Equations in Slope-Intercept Form 5.1 How to find the equation of a line: 1.Find the slope (m) of the line. 2.Find the y-intercept (b) of the line. 3.Plug these values into y = mx + b m = 4 b = 3 y = 4x + 3

10. Example 1 Writing an Equation of a Line Write the equation of the line whose slope m = -2 and whose y-intercept b = 5. y = mx + b

11. Example 1 Writing an Equation of a Line Write the equation of the line whose slope and whose y-intercept. y = mx + b

12. Example 1 Writing an Equation of a Line Write the equation of the line whose slope and whose y-intercept. y = mx + b

13. Example 1 Writing an Equation of a Line Write the equation of the line whose slope m = 1 and whose y-intercept b = 7. y = mx + b

14. Example 2 Writing an Equation of a Line from a Graph Write the equation of the line shown in the graph. 12 34567 1 2 3 5 6 4 7 -6 -2 -4 -6 -4-2 y = mx + b Purple: Blue: Pink: Orange:

15. Example 3 A Linear Model for Population The number of trout in a lake was estimated to be 44.5 thousand in 1995. During the next 10 years, the trout population is expected to increase by about 3.2 thousand per year. Write a linear equation to model the trout population in any year between 1995 and 2005. Let t be the number of years since 1995. Predict the trout population in 2002. P = 3.2t + 44.5 ≈ 66.9 thousand trout

16. Guided Practice Please complete #3-11 on pg. 276 in your textbook. Raise your hand when you are done. 3.9. 4.10. 5. 6. 7. 8.11. 5.1 To be turned in for a classwork grade!

17. Tonight’s Homework pg. 276 #’s 12-19 all, 21-29 odd