1. Splash Screen

2. Lesson Menu Five-Minute Check (over Lesson 2–3) Then/Now New Vocabulary Key Concept:Slope-Intercept Form Example 1:Write an Equation in Slope-Intercept Form Key Concept:Point-Slope Form Example 2:Write an Equation Given Slope and One Point Example 3:Standardized Test Example Key Concept:Parallel and Perpendicular Lines Example 4:Write an Equation of a Perpendicular Line

3. Over Lesson 2–3 A.A B.B C.C D.D 5-Minute Check 1 Find the rate of change for the data. A.–22 gal/mi B.gal/mi C.gal/mi D.22 gal/mi

4. Over Lesson 2–3 A.A B.B C.C D.D 5-Minute Check 2 Find the slope of the line that passes through points (2.3, 9.5) and (3.8, 20). A.–7 B. C.7 D.

5. Over Lesson 2–3 A.A B.B C.C D.D 5-Minute Check 3 A.–1 B.0 C.1 D.3 Find the slope of the line that passes through points (3, 5) and (–6, 5).

6. Over Lesson 2–3 A.A B.B C.C D.D 5-Minute Check 4 Determine the rate of change of the graph. A.–3 B. C. D.3

7. Over Lesson 2–3 A.A B.B C.C D.D 5-Minute Check 5 A.72 cm B.108 cm C.432 cm D.648 cm

8. Then/Now You determined slopes of lines. (Lesson 2–3) Write an equation of a line given the slope and a point on the line. Write an equation of a line parallel or perpendicular to a given line.

9. Vocabulary slope-intercept form point-slope form parallel perpendicular

10. Concept 1

11. Example 1 Write an Equation in Slope-Intercept Form Write an equation in slope-intercept form for the line. Step 1Find the slope. Slope formula (x 1, y 1 ) = (–1, 4), (x 2,y 2 ) = (2, 3) Simplify.

12. Example 1 Write an Equation in Slope-Intercept Form Step 2Use the slope and a point to find the y-intercept. Slope-intercept form Simplify. The y-intercept is

13. Example 1 Write an Equation in Slope-Intercept Form Step 3Substitute the values into the slope-intercept equation. Slope-intercept form

14. A. B. C. D. A.A B.B C.C D.D Example 1 Write an equation in slope- intercept form for the line.

15. Concept 2

16. Example 2 Write an Equation Given Slope and One Point Point-slope form Simplify.

17. Example 2 Write an Equation Given Slope and One Point Answer: Subtract 2 from each side.

18. A.A B.B C.C D.D Example 2 A. B. C. D.

19. Example 3 What is an equation of the line through (2, –3) and (–3, 7)? Read the Test Item You are given the coordinates of two points on the line. ABCDABCD

20. Example 3 Solve the Test Item Step 1Find the slope of the line. The slope is –2. That eliminates choices B and C. Slope formula (x 1, y 1 ) = (2, –3), (x 2,y 2 ) = (–3, 7) Simplify.

21. Example 3 Step 2Write an equation. Use either ordered pair for (x 1, y 1 ). Answer: D Point-slope form m = –2; (x 1, y 1 ) = (2, –3) Simplify. Subtract 3 from each side.

22. A.A B.B C.C D.D Example 3 Which is an equation of the line that passes through (2, 5) and (–1, 3)? A. B. C. D.

23. Concept

24. Example 4 Write an Equation of a Perpendicular Line Write an equation in slope-intercept form for the line that passes through (3, –2) and is perpendicular to the line whose equation is y = –5x + 1.

25. Example 4 Write an Equation of a Perpendicular Line Answer: Distributive Property Point-slope form Subtract 2 from each side.

26. A.A B.B C.C D.D Example 4 A. B. C. D.

27. End of the Lesson