Unit 9: Quadratics Intercept Form

Transcription

1 For Teacher Use Packet Score: Name: Period: Algebra 1 Unit 9: Quadratics Intercept Form Note & Homework Packet Date Topic/Assignment HW Page 9-A Graphing Parabolas in Intercept Form 9-B Solve Quadratic Equations Graphically - Intercept Form 9-C Find Zeros/Solve by Factoring 9-D Complete the Square Standard Form to Vertex Form 9-E Solve Quadratic Equations by Completing the Square 9-F Solve Quadratic Equations by the Quadratic Formula 9-G Graph Quadratic Functions in Standard Form 9-H Graph Quadratic Functions in Standard Form Part 2 9-I Applications of Quadratic Functions 9-J Comparing Different Forms of Quadratic Equations & Transformations Due Date Score (For Teacher Use Only) Quizzes will be pop 2 or 3 per unit. You may use this packet to complete the quizzes. This packet will be turned in on the day of the test for 100 points. Whenever you re absent, you can get these notes filled out from a classmate or at my website During the unit, I ll check off homework each day to keep track of who is doing their homework, but your homework assignments won t be scored and entered into IC until this packet is collected and graded at the end of the unit. 1

2 Warm-Up Date: Graph each parabola. State the domain and range. Warm-Up Date: Warm-Up Date: 2

3 Warm-Up Date: Warm-Up Date: Warm-Up Date: Warm-Up Date: Warm-Up Date: Warm-Up Date: Warm-Up Date: Warm-Up Date: Warm-Up Date: Warm-Up Date: Warm-Up Date: Warm-Up Date: 3

4 9-A: Graphing Parabolas in Intercept Form Review Vertex Form f(x) = a(x h) 2 + k Label each as either Intercept or Vertex Form. f(x) = (x + 9) 2 4 f(x) = 1 (x 4)(x + 2) f(x) = 1 (x 2)2 3 2 f(x) = 2(x 3)(x 5) f(x) = (x + 9) 2 4 f(x) = 3x How is Intercept Form different from Vertex Form? Intercept Form f(x) = ±a(x r)(x s) Steps for graphing in Intercept Form: Go back to the six functions above, state either the intercepts or the vertex for each. 4

5 1. Example Graph each. State the intercepts, vertex, AOS, domain and range. a. f(x) = (x + 3)(x 1) b. f(x) = (x + 1)(x 3) 2. Guided Practice a. f(x) = (x 1)(x 5) b. f(x) = (x 2)(x 4) 3. Example a. f(x) = (x 2)(x 4) b. f(x) = 2(x + 3)(x + 1) 5

6 4. Guided Practice a. f(x) = (x + 2)(x 2) b. f(x) = 2(x 3)(x 5) 5. Example 6. Guided Practice y = 1 (x 2)(x 6) y = 1 (x + 1)(x 3) 2 2 6

7 7. Example Write the equation in INTERCEPT FORM for the parabola shown. a. b. 8. Guided Practice a. b. c. Which of these can you also write in VERTEX FORM? Do so on those that you can. 7

8 9-B: Solve Quadratic Equations Graphically Intercept Form The solutions are the x values of the intersections of f(x) and g(x) when f(x) = g(x). 1. Example Solve by graphing. a. (x 1)(x 3) = 5 b. (x + 2)(x + 6) = 3 f(x) = f(x) = g(x) = g(x) = 2. Guided Practice a. (x 1)(x + 3) = 3 b. (x 3)(x 5) = 3 f(x) = f(x) = g(x) = g(x) = 8

9 3. Example a. 2(x 1)(x 3) = 2 b. 1 (x + 1)(x + 5) = f(x) = f(x) = g(x) = g(x) = 4. Guided Practice a. 2(x + 1)(x + 3) = 6 b. 1 (x 1)(x 5) = f(x) = f(x) = g(x) = g(x) = 9

10 5. Example a. (x 2)(x 6) = 3 b. 1 (x + 2)(x + 6) = f(x) = f(x) = g(x) = g(x) = 6. Guided Practice a. 2(x 2)(x 4) = 6 b. (x 1)(x + 3) = 5 f(x) = f(x) = g(x) = g(x) = 10

11 9-C: Find Zeros/Solve by Factoring What are zeros? Number of Solutions of a Quadratic Equations 1. Example Find the roots/zeros/intercepts/solutions. a. f(x) = (x + 5)(x 3) b. y = (x 6)(x 2) c. f(x) = 1 (x 1)(x + 7) 2 2. Guided Practice a. f(x) = (x 10)(x + 1) b. y = (x + 5)(x 2) c. f(x) = 1 (x + 4)(x 9) 2 3. Example Convert from Standard Form to Intercept Form by factoring. a. f(x) = x 2 + 7x + 10 b. f(x) = x 2 6x + 5 c. f(x) = x 2 + 3x 18 Now name the roots/intercepts/zeros/solutions of each. a. b. c. 11

12 4. Guided Practice Convert to Intercept Form by factoring. a. f(x) = x 2 + 9x + 18 b. f(x) = x 2 9x + 14 c. f(x) = x 2 + 3x 10 Now name the roots/intercepts/zeros/solutions of each. a. b. c. 5. Example Find the zeros. a. f(x) = 2x 2 + 7x + 3 b. f(x) = 3x 2 16x + 5 c. f(x) = 2x 2 + x 6 6. Guided Practice a. f(x) = 3x 2 + 5x + 2 b. f(x) = 2x 2 7x + 3 c. f(x) = 3x 2 x 2 7. Example Solve each equation by factoring. a. x x + 36 = 0 b. x 2 7x + 12 = 0 c. 2x 2 + 9x 5 = 0 12

13 8. Guided Practice Solve each equation by factoring. a. x 2 8x + 15 = 0 b. x 2 2x 15 = 0 c. 2x 2 5x + 3 = 0 9. Example Solve by factoring. a. 3x x = 4 b. 2x 2 7x = Guided Practice a. x 2 7x = 12 b. x 2 2x = 15 13

14 9-D: Complete the Square Standard Form to Vertex Form Vertex Form Intercept Form Standard Form y = a(x h) 2 + k y = a(x r)(x s) y = ax 2 + bx + c How do we convert Vertex or Intercept form into Standard form? 1. Example Convert each quadratic equation to Standard Form. a. f(x) = (x + 2) 2 3 b. y = (x 3) c. f(x) = (x + 2)(x 4) 2. Guided Practice a. f(x) = (x 4) 2 2 b. f(x) = (x + 1) 2 5 c. y = (x + 5)(x + 2) How do we convert Standard Form to Intercept Form? Now we re going to convert Standard Form to Vertex Form. First, we need to review Perfect Square Trinomials. Perfect Square Trinomials Factored Form x 2 + 8x + 16 x 2 10x x x

15 3. Example Find the value of c that makes the expression a perfect square trinomial. Then write the expression as a binomial squared (factored form). a. x 2 + 6x + c b. x 2 + 8x + c c. x 2 10x + c 4. Guided Practice a. x 2 + 2x + c b. x 2 8x + c c. x 2 + 6x + c Why is c always positive in a perfect square trinomial? 5. Example Convert from Standard Form to Vertex Form by Completing the Square. a. y = x 2 + 6x + 3 b. y = x 2 + 4x 5 c. f(x) = x 2 8x 1 5. Guided Practice a. y = x x + 3 b. f(x) = x 2 6x + 2 c. y = x 2 2x 7 15

16 What if a > 1? 6. Example a. f(x) = 2x 2 + 8x + 5 b. y = 3x 2 12x Guided Practice a. y = 2x 2 10x 7 b. f(x) = 3x x 2 What is the extra step we need to remember when a > 1? 16

17 9-E: Solve Quadratic Equations by Completing the Square 1. Example Solve the quadratic equation by completing the square. a. x x 51 = 0 b. x 2 12x + 10 = 0 2. Guided Practice a. x 2 + 6x + 8 = 0 b. x 2 2x 4 = 0 Remember what to do when a > 1? 3. Example a. 5x 2 = 60 20x b. 6x 2 48 = Guided Practice a. 8x x = 42 b. 3x 2 = 4 + 8x 17

18 9-F: Solve Quadratic Equations by the Quadratic Formula What are all of the ways that we can solve quadratic equations? Here s another 1. Example Solve using the quadratic formula. a. b. 2. Guided Practice a. b. 18

19 3. Example a. b. 4. Guided Practice a. b. c. d. 19

20 9-G: Graph Quadratic Functions in Standard Form Name all different graphing forms of quadratic functions. Here s another way to graph parabolas Standard Form Step 1: Find the Vertex and plot it on the grid. Axis of Symmetry Step 2: Use a to draw the legs Example 1. y = x 2 4x y = x 2 + 4x + 1 Guided Practice 3. y = x 2 6x y = x 2 6x

21 Example Guided Practice 5. y = x 2 + 8x y = x 2 + 4x 5 Example Write the equation in standard form for the parabola shown Guided Practice 9. 21

22 9-H: Graph Quadratic Functions in Standard Form Part 2 Example 1. y = 2x 2 + 4x 4 2. y = 1 2 x2 + 2x Guided Practice 3. y = 2x 2 8x y = 1 2 x2 4x

23 Example Guided Practice 5. f(x) = 2x 2 4x f(x) = 1 2 x2 4x 6 Example Write the equation for the quadratic function shown Guided Practice 9. 23

24 9-I: Applications of Quadratic Functions 1. Below is a graph for the P profits for various selling prices s of a skateboard

25 4. 5. Find the value of x

26 9-J: Comparing Different Forms of Quadratic Equations & Transformations 26

27 Write the equation for the parabola described. A graph is provided if needed. 3. Translate the graph f(x) = x 2 up three units and two units right. What is the new equation? 5. Translate the graph y = (x 1)(x 5) nine units up and three units left. What is the new equation? 27

28 9-A Assignment Graph each. State the x-intercepts and vertex for each. 1. y = (x 1)(x 3) 2. y = (x + 3)(x + 1) 3. y = (x 1)(x 3) 4. y = (x + 1)(x 3) 5. y = 2(x 1)(x 3) 6. y = 2(x 1)(x 3) Write the equation in Intercept Form AND Vertex Form for the parabola shown

29 9-B Assignment Solve each quadratic equation graphically. 1. (x + 3)(x + 5) = 3 2. (x 2)(x 4) = (x + 2)(x + 4) = (x + 3)(x + 7) = (x 3)(x 5) = (x + 2)(x + 4) = 6 29

30 9-C Assignment Find the roots of each quadratic function. 1. y = (x 4)(x = 7) 2. f(x) = x 2 + 8x f(x) = 2x x + 15 Convert to Intercept Form by factoring. 4. f(x) = x 2 6x 7 5. f(x) = x 2 + 3x y = 3x 2 11x + 6 Now name the roots for problems Solve each equation by factoring. 7. x 2 + 3x 18 = 0 8. x 2 7x + 12 = x 2 + x 6 = x 2 11x = x 2 + 9x = x 2 2x = 15 30

31 9-D Assignment Convert each quadratic equation to Standard Form. 1. f(x) = (x + 4) y = (x 5) f(x) = (x + 3)(x 5) Find the value of c that makes the expression a perfect square trinomial. Then write the expression as a binomial squared (factored form). 4. x x + c 5. x 2 + 2x + c 6. x 2 14x + c Convert from Standard Form to Vertex Form by Completing the Square. 7. y = x 2 + 4x y = x x 2 9. f(x) = x 2 14x y = x 2 12x y = 2x 2 + 8x f(x) = 3x 2 15x

32 9-E Assignment Solve each equation by completing the square. 1. x x 15 = 0 2. x 2 = 18x x 2 = 6 + 8x 4. x 2 + 2x 3 = 0 5. x 2 2x 7 = 0 6. x 2 + 8x + 12 = 0 7. x 2 2x 48 = 0 8. x x + 21 = 0 9. x 2 8x 48 = x 2 14x 56 = x x = x 2 6x = 7 32

33 9-F Assignment Solve by using the quadratic formula. 33

34 9-G Assignment Graph. Label the vertex and axis of symmetry. 1. f(x) = x 2 8x f(x) = x 2 2x 3 3. f(x) = x 2 4x 4. f(x) = x 2 + 6x 4 5. f(x) = x 2 + 4x f(x) = x 2 + 4x + 2 Write the equation for the parabola shown

35 9-H Assignment Graph. Label the vertex and axis of symmetry. 1. y = 2x 2 4x 4 2. y = 1 2 x2 + 4x y = 1 2 x2 + 2x y = 2x 2 + 8x 4 Write the equation for the parabola shown

36 9-I Assignment 1. Given the graph of a ball being thrown from a catapult, answer the following questions. The vertical axis represents the height of the ball, the horizontal axis represents the distance from the catapult. a. How far away from the catapult does the ball land? What part of the graph tells you this? b. What is the maximum height the ball goes? What part of the graph tells you this? c. Is the value of a positive or negative? How do you know? 2. You throw a basketball whose path can be modeled by the graph of y = 16x x + 6 where x is the time (in seconds) and y is the height (in feet) of the basketball

37 4. 5. Find the value of x

38 9-J Assignment 3. Translate the graph f(x) = x 2 up 5 units and 3 units right. What is the new equation? 5. Translate the graph y = (x + 1) 2 2 down 7 units and 4 units left. What is the new equation? 38