Lesson Plan – 1 – Algebra I Introduction Lesson Topic: Factoring Quadratic Polynomials Length of Lesson: 90 Minutes VA Standards of Learning: A.2.c – The student will factor completely first- and seconddegree binomials and trinomials in one or two variables. Context: This is the fifth class in a series of nine (block) classes on polynomials and factoring. The students will have completed the first four sections on adding and subtracting polynomials, simple factoring, multiplying binomials and multiplying polynomials. Global Themes: This lesson is part of the chapter teaching that a single quantity can be represented by many different equations/expressions and how these equations/expressions can be broken into piece parts by a process known as factoring. Content Objectives 1. The student will factor a polynomial in one or two variables. Assessment Aligned to Objectives 1. The student will factor a polynomial in one or two variables. Formative: Following the first portion of the lecture, the teacher will first work problems from a worksheet with the students asking the students to contribute to the solutions. The teacher will check for comprehension among the students as he or she works through the problems of this worksheet. After the second portion of the lecture the students will work on a second worksheet independently with the teacher checking each student’s progress by walking around. Students who are slower to work the problems will be given assistance and a supplemental factoring worksheet with numbers only. Students who are able to complete the worksheet without difficulty will be assigned iPad app SAT prep questions related to polynomial factoring. Materials/Technology and Advanced Preparation Algebra 1 text (used in preparation and homework assessment) Computer (for teacher use) PowerPoint presentation Projector and screen Whiteboard Worksheet 1 – Teacher Led Worksheet 2 – Student Independent Worksheet 3 – Factoring Drill iPads with SAT Prep application loaded (for student use) Before class, computer and projector must be set up, enough copies of worksheet 1 must be printed, and slope demonstration must be set up at the front of the room. Algebra I Lesson Plan – Factoring Bechter 2 Teaching and Learning Sequence TIME TEACHER ACTIONS STUDENT ACTIONS Introduction/Anticipatory Set – Outline how the lesson will begin. How will you focus student attention on lesson content, build on prior knowledge, motivate students to learn, etc.? Ten minutes The teacher shows the YouTube video using algebraic tiles to help conceptualize factoring of quadratic polynomials. After the video has finished the teacher reiterates the basic concept of the video which is that the two factors of a polynomial can be thought of as the measure of the length and width of a rectangle. The student gains a different perspective and understanding of the factors of a quadratic polynomial that is analogous to their existing understanding of finding the area of a rectangle using the length and width. Lesson Development – Outline the sequence to be followed in the development of the lesson. Pay particular attention to concept development and questioning. Fifteen minutes The teacher gives first portion of lecture on factoring quadratic polynomials of the form ax2+bx+c using the possible factors with sums table approach. The student sees the approach to factoring using factors of “c” term using factors with sums table approach. Twenty minutes The teacher works a 6 problem worksheet with student input. The students, as a group, raise hands to contribute to each step of the process in factoring each of the six problems on the worksheet. Fifteen minutes The teacher gives second portion of lecture on factoring, this time with a second variable showing how it does not matter in the method used to do the factoring. The student sees the approach to factoring using factors of “c” term using factors with sums table approach with two variables in quadratic polynomial. Twenty minutes The teacher distributes worksheet 2 and monitors student work. Slower students given number factoring drill sheet. Students who complete the worksheet assigned SAT test prep iPad app work. The student working independently works the factoring problems on the worksheet. Five minutes The teacher assigns the homework. The student writes down the homework assignment. Closure – Outline how the lesson will be concluded. How will you summarize, review, reinforce, enrich, and/or encourage students to reflect on what they have learned? Algebra I Lesson Plan – Factoring Five minutes Teacher asks students as a group a closing set of questions about the approach to factoring. Teacher assesses how well students remembered key points. Bechter 3 Students respond to questions about the factoring process to show they understand. Homework The homework assigned will be as follows: Page 504 – 32-40, 44-48; Page 505 – 49-60, 71-73 in the Algebra 1 text. This will be assigned at the very end of the class. The assignment covers everything that was discussed in class and will be turned in at the beginning of the next class and graded for completion. The next class material builds on this material and a review of the homework will be built in to the introduction of the new material that introduces a non-unity “a” term in the quadratic expression to be factored. References Randall I. Charles, Basia Hall, Dan Kennedy, Allan E. Bellman, Sadie Chavis Bragg, William G. Handlin, Stuart J. Murphy, Grant Wiggins (2012). Prentice Hall Algebra 1. YouTube video: Expanded and Factored forms using Algebra Tiles - MrAlgebra9 http://www.youtube.com/watch?v=BXyI1nReQjc Appended Materials Attach the following forms and resources to the completed lesson plan. Lesson Organizer Curriculum Framework Document PowerPoint Presentation including o Worksheet 1 o Worksheet 2 Supplemental Worksheet – Factoring Drill Assigned Homework Algebra I Lesson Plan – Factoring Bechter 4 Lesson Organizer Prior Knowledge and NEW Instructional Content Previously students have studied how to add like terms in polynomials, multiply binomials using “FOIL” (first, outside, inside, last) technique, and do simple factoring of a single variable and/or constant within a quadratic expression. Opening Activity o YouTube Video – Expanded and Factored Forms Using Algebraic Tiles o Ask questions after video: So if a rectangle has sides measuring (x+1) and (x+2) what is the area of the rectangle? Use whiteboard to show a rectangle with sides x+3 and x+4. Ask: If I show a rectangle with these sides what is its area? Lecture (part 1): Approach for Factoring Quadratic Polynomials (using PowerPoint slides 1 – 5) o Slide 1 To factor quadratic polynomials you must be able to factor the constant or “c” term in the expression ax2+bx+c form. Let’s go over a couple examples and look at the sums and differences for each just to get our math juices flowing If we factor 24 in all the ways possible we see that there are 4 factor pairs and 8 total factors. 24&1, 12&2, 8&3 and 6&4. The sums and differences of each of these factor pairs are shown after the factors: 24&1 give a sum of 25 and a difference of 23; 12&2 sum to 14 and have a difference of 10; 8&3 sum to 11 and have a difference of 5 and finally 6&4 add to 10 and have a difference of 2. When we factor a polynomial the “b” term will come from these sums or differences Let’s factor 36 now There are 5 factor pairs for 36: 36&1, 18&2, 12&3, 9&4 and finally the perfect square factor 6. Sums for these 5 pairs: 37, 20, 15, 13, 12. Differences 35, 16, 9, 5, 0 Why do we go over this? o Slide 2 Because this skill is critical in factoring polynomials!! A quick review of FOIL, remember “FOIL” – first/first, outside/outside, inside/inside, last/last? One quick example: (x+3)(x+4), just like we just did on the board to show the rectangle made up of length and width with these measures, gives – first/first: x*x=x2, outside/outside: x*4=4x, inside/inside: 3*x=3x, last/last: 3*4=12. Adding like terms 4x & 3x gives 7x and you can write the quadratic expression x2+7x+12 Factoring is the reverse of FOILing! So if we find the length and width of a rectangle with area x2+7x+12 we Algebra I Lesson Plan – Factoring Bechter 5 get that its sides are (x+3) and (x+4) long. o Slide 3 Let’s do some examples Our first problem is to factor x2+8x+15 What are the factor pairs for 15? 15&1 and 5&3 All positive signs in the quadratic expression so we focus on sums only here. 5&3 give a sum of 8 so they are our constant terms in the two binomials we get when we factor. Answer (x+5) and (x+3) Any questions? o Slide 4 Our next example also has 15 for the “c” term in our quadratic polynomial. However in this case our “c” term has a negative sign so now we are going to be looking at differences in the factors Since one sign must be negative and the other positive let’s look at all the factor pairs that will give us negative 15 and see what there sums are (differences really but let’s think of them as adding a positive and a negative so that we can always write sum above the column) Positive 15 and negative 1 sum to positive 14, negative 15 and positive 1 add to negative 14, positive 5 and negative 3 add to 2 (there’s our solution), and for completion sake, negative 5 and positive 3 add to negative 2. Our factors? (x+5) and (x-3) Any questions? o Slide 5 One more example and then let’s work some together Let’s factor x2-11x+24. Here we have a positive “c” term and a negative “b” term. How do we get factors to make this work? Remembering that a negative plus a negative gives a negative and a negative times a negative gives a positive we realize that both factors must be negative So to get a positive 24 for the “c” or constant term and a negative for the “b” term in front of x we will be factoring 24 in pairs with both numbers negative. Negative 24 and negative 1 multiply to 24 and their sum is 25, negative 12 and negative 2 multiply to 24 and their sum is negative 14, negative 8 and negative 3 multiply to 24 and their sum is negative 11. There is our answer! But to complete the factoring table…negative 6 and negative 4 multiply to 24 and sum to negative 10. Our factors: (x-8) & (x-3). Worksheet 1 worked together: Problem-by-problem worked out on the SmartBoard calling on individual students to tell the teacher how to solve the problems. Take time here to work through each problem systematically by first Algebra I Lesson Plan – Factoring Bechter 6 examining the signs of the “b” and “c” terms, then factoring the “c” constant term and checking the sums of each factor pair. Ask each time: “B-term is positive or negative? C-term is positive or negative? How do we factor the c-term to make this work out? (Answer: for c-term to be negative it must be a negative times a positive, for it to be positive it can either be positive times a positive or a negative times a negative; for the b-term if both factor pairs are positive the b-term will necessarily be positive, if both factor pairs are negative the b-term will necessarily be negative. When the c-term is negative then for the b term to be positive the larger of the c-term factors must be positive and the other smaller factors must be negative. For the b-term to be negative when the c-term is negative the larger of the c-term factors must be negative and the other smaller term must be positive.) Lecture (part 2): Approach for factoring Quadratic Polynomials (using Power Point slides 7-10) o Slide 7 Now that we have done a few examples together when we are dealing with just one variable in the quadratic expression let’s add another variable. Hey, this is really no big deal! Don’t sweat it one bit. Let’s factor x2+xy-42y2 Let’s review our b and c terms first. The c-term is negative 42. The bterm is what? (Answer: positive 1) How do you get the final term to have a y-squared? (answer: y*y, a y ends each of the factored binomials) So to get a negative c-term we need one positive and one negative factor. Negative 42 and positive 1 add to negative 41, positive 42 and negative 1 add to positive 41, negative 21 and positive 2 add to negative 19, positive 21 and negative 2 add to positive 19, negative 7 and positive 6 add to negative 1, and finally, positive 7 and negative 6 add to positive 1. There’s our answer! So to write the factors for the quadratic expression with two binomials we have (x+7y) and (x-6y). A quick check using FOIL…x*x is certainly x-squared, x*(-6y) is -6xy, and 7y*x is 7xy, and 7y*(-6y) is -42y-squared. Combining like terms with xy and we get positive xy. We are good! o Slide 8 Okay let’s do one where we use something besides x&y as our variables Let’s factor s2-3st-54t2. C-term is negative, b-term is negative. What will our factor constants have for signs? (Answer: One term is positive and the other negative because that is the only way you can get a negative with multiplication, because b-term is negative the larger constant will be negative.) Factoring with this in mind we really only need to look at the first, third and fifth factor pairs right? (Look for understanding in the classroom) Ask: So what is the form of the factored expression? (Answer: two Algebra I Lesson Plan – Factoring Bechter 7 binomials multiplied together with s and t as variables and factor pair that works as constants, one each, with proper sign.) o Slide 9 Okay, one more example and then I will set you free to practice and show me how well (or not) you understand. For those of you who are having trouble factoring the constant I have an additional worksheet that simply focuses on the numerical part of this skill. For those of you who get it and can complete the worksheet within the 20 minutes I will ask you to take out your iPads and work on the SAT prep in this area. If you complete a prep quiz I will ask that you raise your hand and let me know your score. Alright, here we have an expression using p and q as variables. P216pg+48q2. Help me with the b- and c-term signs. (should get from students that bterm is negative and c-term is positive so that the factors must both be negative) Factoring -48: -48/-1, -24/-2, -16/-3, -12/-4 (correct answer), and -8/-6 So we write our factor binomials…(p-12q)*(p-4q) Check it. p*p is p-squared, -4pq+(-12pq) is -16pq, and -12q*-4q is 48q2. All is well! Pass out paper worksheet of Slide 10 for students to work independently. Worksheet 2 students work independently o While students work this worksheet the teacher is walking around looking at the speed at which his/her students are solving and writing the factor binomials. o Those students who are moving quickly and getting the answers correct will be instructed to complete the worksheet, hand it in, and then work on the SAT prep quizzes on their iPads using the SAT Test Prep app. o Those students who are not progressing and are having trouble factoring the cterm will be given the supplemental worksheet on factoring and told to work on it first before returning to Worksheet 2. Homework assignment o Teacher gives out the homework assignment: page 504 – 32-40, 44-48; page 505 – 49-60, 71-73. o Tell students that they have 3 multiple choice that essentially require that they FOIL to get the right answer, 21 factoring problems all similar to what was covered in class, 2 reasoning problems that check for understanding of method, and 3 problems that require simple factoring that will help prepare them for the next lesson. None of these problems individually should take more than a minute to do if you are not distracted and focused. I expect this assignment to be completed within a half-hour. If you are not able to do these factoring problems this quickly I want to talk with you during our next class. Closing Activity (PowerPoint slide 11) o Review of approach to factoring Algebra I Lesson Plan – Factoring Bechter 8 o Preview of next lesson when a-term is not 1 and how that one difference requires just a single additional step. o Ask if there are any questions about the homework or about anything done in class today. o Class dismissed. Instructional Modifications to ASSIST Students Main Events of Instruction Instructional Modifications to CHALLENGE Students Anticipatory Set: YouTube video Lecture: Factoring ax2+bx+c format quadratic polynomials. Worksheet 1 worked through with student input Lecture: Factoring ax2+bx+cy2 format (two variable) quadratic polynomials Supplemental worksheet of factoring common multiples given out. Worksheet 2 worked by students independently. Homework assigned. Closing activity: Summarizing Q&A SAT Test Prep on iPads Algebra I Lesson Plan – Factoring Bechter 9 STANDARD A.2.c ESSENTIAL UNDERSTANDINGS The laws of exponents can be investigated using inductive reasoning. A relationship exists between the laws of exponents and scientific notation. Operations with polynomials can be represented concretely, pictorially, and symbolically. Polynomial expressions can be used to model real-world situations. The distributive property is the unifying concept for polynomial operations. Factoring reverses polynomial multiplication. Some polynomials are prime polynomials and cannot be factored over the set of real numbers. Polynomial expressions can be used to define functions and these functions can be represented graphically. There is a relationship between the factors of any polynomial and the xintercepts of the graph of its related function. ESSENTIAL KNOWLEDGE AND SKILLS The student will use problem solving, mathematical communication, mathematical reasoning, connections, and representations to Simplify monomial expressions and ratios of monomial expressions in which the exponents are integers, using the laws of exponents. Model sums, differences, products, and quotients of polynomials with concrete objects and their related pictorial representations. Relate concrete and pictorial manipulations that model polynomial operations to their corresponding symbolic representations. Find sums and differences of polynomials. Find products of polynomials. The factors will have no more than five total terms (i.e. (4x+2)(3x+5) represents four terms and (x+1)(2x2 +x+3) represents five terms). Find the quotient of polynomials, using a monomial or binomial divisor, or a completely factored divisor. Factor completely first- and second-degree polynomials with integral coefficients. Identify prime polynomials. Use the x-intercepts from the graphical representation of the polynomial to determine and confirm its factors.