1. Splash Screen

2. Lesson Menu Five-Minute Check (over Lesson 3–3) CCSS Then/Now New Vocabulary Key Concept: Nonvertical Line Equations Example 1:Slope and y-intercept Example 2:Slope and a Point on the Line Example 3:Two Points Example 4:Horizontal Line Key Concept: Horizontal and Vertical Line Equations Example 5:Write Equations of Parallel or Perpendicular Lines Example 6:Real-World Example: Write Linear Equations

3. Over Lesson 3–3 5-Minute Check 1 A. B. C. D. What is the slope of the line MN for M(–3, 4) and N(5, –8)?

4. Over Lesson 3–3 5-Minute Check 2 A. B. C. D. What is the slope of a line perpendicular to MN for M(–3, 4) and N(5, –8)?

5. Over Lesson 3–3 5-Minute Check 3 A. B. C. D. What is the slope of a line parallel to MN for M(–3, 4) and N(5, –8)?

6. Over Lesson 3–3 A.B. C.D. 5-Minute Check 4 What is the graph of the line that has slope 4 and contains the point (1, 2)?

7. Over Lesson 3–3 5-Minute Check 5 What is the graph of the line that has slope 0 and contains the point (–3, –4)? A.B. C.D.

8. Over Lesson 3–3 5-Minute Check 6 A.(–2, 2) B.(–1, 3) C.(3, 3) D.(4, 2)

9. CCSS Content Standards G.GPE.5 Prove the slope criteria for parallel and perpendicular lines and use them to solve geometric problems (e.g., find the equation of a line parallel or perpendicular to a given line that passes through a given point). Mathematical Practices 4 Model with mathematics. 8 Look for and express regularity in repeated reasoning.

10. Then/Now You found the slopes of lines. Write an equation of a line given information about the graph. Solve problems by writing equations.

11. Vocabulary slope-intercept form point-slope form

12. Concept

13. Example 1 Slope and y-intercept Write an equation in slope-intercept form of the line with slope of 6 and y-intercept of –3. Then graph the line. y = mx + bSlope-intercept form y = 6x + (–3)m = 6, b = –3 y = 6x – 3 Simplify.

14. Example 1 Slope and y-intercept Answer: Plot a point at the y-intercept, –3. Use the slope of 6 or to find another point 6 units up and 1 unit right of the y-intercept. Draw a line through these two points.

15. Example 1 A.x + y = 4 B.y = x – 4 C.y = –x – 4 D.y = –x + 4 Write an equation in slope-intercept form of the line with slope of –1 and y-intercept of 4.

16. Example 2 Slope and a Point on the Line Point-slope form Write an equation in point-slope form of the line whose slope is that contains (–10, 8). Then graph the line. Simplify.

17. Example 2 Slope and a Point on the Line Answer: Graph the given point (–10, 8). Use the slope to find another point 3 units down and 5 units to the right. Draw a line through these two points.

18. Example 2 Write an equation in point-slope form of the line whose slope is that contains (6, –3). A. B. C. D.

19. Example 3 Two Points A. Write an equation in slope-intercept form for a line containing (4, 9) and (–2, 0). Step 1 First, find the slope of the line. Slope formula x 1 = 4, x 2 = –2, y 1 = 9, y 2 = 0 Simplify.

20. Example 3 Two Points Step 2 Now use the point-slope form and either point to write an equation. Distributive Property Add 9 to each side. Answer: Point-slope form Using (4, 9):

21. Example 3 Two Points B. Write an equation in slope-intercept form for a line containing (–3, –7) and (–1, 3). Step 1 First, find the slope of the line. Slope formula x 1 = –3, x 2 = –1, y 1 = –7, y 2 = 3 Simplify.

22. Example 3 Two Points Step 2 Now use the point-slope form and either point to write an equation. Distributive Property Answer: m = 5, (x 1, y 1 ) = (–1, 3) Point-slope form Using (–1, 3): Add 3 to each side. y = 5x + 8

23. Example 3a A. Write an equation in slope-intercept form for a line containing (3, 2) and (6, 8). A. B. C. D.

24. Example 3b A.y = 2x – 3 B.y = 2x + 1 C.y = 3x – 2 D.y = 3x + 1 B. Write an equation in slope-intercept form for a line containing (1, 1) and (4, 10).

25. Example 4 Horizontal Line Write an equation of the line through (5, –2) and (0, –2) in slope-intercept form. Slope formula This is a horizontal line. Step 1

26. Example 4 Horizontal Line Point-Slope form m = 0, (x 1, y 1 ) = (5, –2) Step 2 Answer: Simplify. Subtract 2 from each side.y = –2

27. Example 4 Write an equation of the line through (–3, 6) and (9, –2) in slope-intercept form. A. B. C. D.

28. Concept