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8-3 Multiplying Polynomials ANSWER: 2 4x + 72x + 320 Find each product. 1. (x + 5)(x + 2) ANSWER: 2 x + 7x + 10 2. (y − 2)(y + 4) ANSWER: 2 y + 2y − 8 Find each product. 2 8. (2a − 9)(3a + 4a − 4) ANSWER: 3 2 6a − 19a − 44a + 36 2 2 9. (4y − 3)(4y + 7y + 2) ANSWER: 4 3 2 16y + 28y − 4y − 21y − 6 3. (b − 7)(b + 3) ANSWER: 2 b − 4b − 21 2 2 10. (x − 4x + 5)(5x + 3x − 4) ANSWER: 4 3 4. (4n + 3)(n + 9) ANSWER: 2 4n + 39n + 27 2 5x − 17x + 9x + 31x − 20 2 2 11. (2n + 3n − 6)(5n − 2n − 8) ANSWER: 4 3 2 10n + 11n − 52n − 12n + 48 5. (8h − 1)(2h − 3) ANSWER: 2 16h − 26h + 3 6. (2a + 9)(5a − 6) Find each product. 12. (3c − 5)(c + 3) ANSWER: 2 3c + 4c − 15 ANSWER: 2 10a + 33a − 54 7. FRAME Hugo is designing a frame as shown. The frame has a width of x inches all the way around. Write an expression that represents the total area of the picture and frame. 13. (g + 10)(2g − 5) ANSWER: 2 2g + 15g − 50 14. (6a + 5)(5a + 3) ANSWER: 2 30a + 43a + 15 15. (4x + 1)(6x + 3) ANSWER: 2 24x + 18x + 3 ANSWER: 2 4x + 72x + 320 16. (5y − 4)(3y − 1) ANSWER: 2 15y − 17y + 4 Find each product. 2 8. (2a − 9)(3a + 4a − 4) ANSWER: 3 17. (6d − 5)(4d − 7) ANSWER: 2 2 6a Manual 44a +by36Cognero − 19a - − eSolutions Powered 24d − 62d + 35 18. (3m + 5)(2m + 3) 2 2 9. (4y − 3)(4y + 7y + 2) ANSWER: Page 1 2 25. (2y − 11)(y − 3y + 2) 16. (5y − 4)(3y − 1) ANSWER: ANSWER: 8-3 Multiplying Polynomials 2 15y − 17y + 4 3 2 2y − 17y + 37y − 22 2 17. (6d − 5)(4d − 7) 26. (4a + 7)(9a + 2a − 7) ANSWER: ANSWER: 2 3 24d − 62d + 35 2 36a + 71a − 14a − 49 18. (3m + 5)(2m + 3) 2 2 27. (m − 5m + 4)(m + 7m − 3) ANSWER: ANSWER: 2 6m + 19m + 15 4 3 2 m + 2m − 34m + 43m − 12 19. (7n − 6)(7n − 6) 2 2 28. (x + 5x − 1)(5x − 6x + 1) ANSWER: ANSWER: 2 49n − 84n + 36 4 3 2 5x + 19x − 34x + 11x − 1 20. (12t − 5)(12t + 5) 3 2 29. (3b − 4b − 7)(2b − b − 9) ANSWER: ANSWER: 2 144t − 25 5 4 3 2 6b − 3b − 35b − 10b + 43b + 63 21. (5r + 7)(5r − 7) 2 3 30. (6z − 5z − 2)(3z − 2z − 4) ANSWER: 2 ANSWER: 25r − 49 5 4 3 2 18z − 15z − 18z − 14z + 24z + 8 22. (8w + 4x)(5w − 6x) Simplify. ANSWER: 2 2 40w − 28wx − 24x 2 2 31. (m + 2)[(m + 3m − 6) + (m − 2m + 4)] ANSWER: 23. (11z − 5y)(3z + 2y) 3 2 2m + 5m − 4 ANSWER: 2 33z + 7yz − 10y 2 2 2 32. [(t + 3t − 8) − (t − 2t + 6)](t − 4) ANSWER: 24. GARDEN A walkway surrounds a rectangular garden. The width of the garden is 8 feet, and the length is 6 feet. The width x of the walkway around the garden is the same on every side. Write an expression that represents the total area of the garden and walkway. 2 5t − 34t + 56 CCSS STRUCTURE Find an expression to represent the area of each shaded region. ANSWER: 2 4x + 28x + 48 Find each product. 2 25. (2y − 11)(y − 3y + 2) ANSWER: 3 33. ANSWER: 2 2 4πx + 12πx + 9π − 3x − 5x − 2 2 2y − 17y + 37y − 22 2 26. (4a + 7)(9a + 2a − 7) eSolutions Manual - Powered by Cognero ANSWER: 3 2 36a + 71a − 14a − 49 Page 2 33. 39. (x − 5y) ANSWER: 2 2 8-3 Multiplying Polynomials 4πx + 12πx + 9π − 3x − 5x − 2 2 ANSWER: 2 x − 10xy + 25y 40. (2r − 3t) 2 3 ANSWER: 3 2 2 3 8r − 36r t + 54rt − 27t 34. 41. (5g + 2h) ANSWER: 3 ANSWER: 2 24x − 35. VOLLEYBALL The dimensions of a sand volleyball court are represented by a width of 6y − 5 feet and a length of 3y + 4 feet. 42. (4y + 3z)(4y − 3z) 2 ANSWER: 3 2 2 64y − 48y z − 36yz + 27z 3 a. Write an expression that represents the area of the court. b. The length of a sand volleyball court is 31 feet. Find the area of the court. 43. CONSTRUCTION A sandbox kit allows you to build a square sandbox or a rectangular sandbox as shown. ANSWER: a. 18y 2 + 9y − 20 2 b. 1519 ft 36. GEOMETRY Write an expression for the area of a triangle with a base of 2x + 3 and a height of 3x − 1. a. What are the possible values of x? Explain. ANSWER: b. Which shape has the greater area? c. What is the difference in areas between the two? Find each product. 2 37. (a − 2b) ANSWER: a. x > 4; If x = 4 the width of the rectangular sandbox would be zero and if x < 4 the width of the rectangular sandbox would be negative. ANSWER: 2 a − 4ab + 4b 2 38. (3c + 4d) b. square 2 ANSWER: 2 2 9c + 24cd + 16d 39. (x − 5y) c. 4 ft 2 2 44. MULTIPLE REPRESENTATIONS In this problem, you will investigate the square of a sum. ANSWER: 2 x − 10xy + 25y 40. (2r − 3t) 2 3 eSolutions Manual - Powered by Cognero ANSWER: 3 2 2 3 8r − 36r t + 54rt − 27t a. TABULAR Copy and complete the table for each sum. Page 3 square quantities), and apply the FOIL method. For 2 2 2 example, (2x + 3)( x + 5x + 7) = (2x + 3)[ x + (5x 2 2 + 7)] = 2x(x ) + 2x(5x + 7) + 3(x ) + 3(5x + 7). Then use the Distributive Property and simplify. c. 4 ft 8-3 Multiplying Polynomials m 44. MULTIPLE REPRESENTATIONS In this problem, you will investigate the square of a sum. p 46. CHALLENGE Find (x + x )(x m−1 −x 1−p p + x ). ANSWER: a. TABULAR Copy and complete the table for each sum. 47. OPEN ENDED Write a binomial and a trinomial involving a single variable. Then find their product. ANSWER: 2 2 Sample answer: x − 1, x − x − 1. (x − 1) · (x − x − 3 2 1) = x − 2x + 1 b. VERBAL Make a conjecture about the terms of the square of a sum. c. SYMBOLIC For a sum of the form a + b, write an expression for the square of the sum. ANSWER: a. b. The first term of the square of a sum is the first term of the sum squared. The middle term of the sum is two times the first term of the sum multiplied by the last term of the sum. The third term of the square of the sum is the last term of the sum squared. c. a 2 + 2ab + b 2 45. REASONING Determine if the following statement is sometimes, always, or never true. Explain your reasoning. The FOIL method can be used to multiply a binomial and a trinomial. ANSWER: Always; by grouping two adjacent terms, a trinomial can be written as a binomial (the sum of two quantities), and apply the FOIL method. For 2 2 example, (2x + 3)( x + 5x + 7) = (2x + 3)[ x + (5x 2 2 + 7)] = 2x(x ) + 2x(5x + 7) + 3(x ) + 3(5x + 7). Then use the Distributive Property and simplify. m p 46. CHALLENGE Find (x + x )(x m−1 −x 1−p p + x ). ANSWER: eSolutions Manual - Powered by Cognero 47. OPEN ENDED Write a binomial and a trinomial involving a single variable. Then find their product. 48. CCSS REGULARITY Compare and contrast the procedure used to multiply a trinomial by a binomial using the vertical method with the procedure used to multiply a three-digit number by a two-digit number. ANSWER: The three monomials that make up the trinomial are similar to the three digits that make up the 3-digit number. The single monomial is similar to a 1-digit number. With each procedure you perform 3 multiplications. The difference is that polynomial multiplication involves variables and the resulting product is often the sum of two or more monomials, while numerical multiplication results in a single number. 49. WRITING IN MATH Summarize the methods that can be used to multiply polynomials. ANSWER: The Distributive Property can be used with a vertical or horizontal format by distributing, multiplying, and combining like terms. The FOIL method is used with a horizontal format. You multiply the first, outer, inner, and last terms of the binomials and then combine like terms. A rectangular method can also be used by writing the terms of the polynomials along the top and left side of a rectangle and then multiplying the terms and combining like terms. 50. What is the product of 2x − 5 and 3x + 4? A 5x − 1 B 6x2 − 7x − 20 2 C 6x − 20 D 6x2 + 7x − 20 ANSWER: B 51. Which statement is correct about the symmetry of this design? Page 4 2 C 6x − 20 D 6x2 + 7x − 20 D T ANSWER: Polynomials 8-3 Multiplying B ANSWER: D 51. Which statement is correct about the symmetry of this design? 53. SHORT RESPONSE For a science project, Jodi selected three bean plants of equal height. Then, for five days, she measured their heights in centimeters and plotted the values on the graph below. F The design is symmetrical only about the y-axis. G The design is symmetrical only about the x-axis. H The design is symmetrical about both the y- and the x-axes. She drew a line of best fit on the graph. What is the slope of the line that she drew? ANSWER: J The design has no symmetry. ANSWER: F 52. Which point on the number line represents a number that, when cubed, will result in a number greater than itself? 54. SAVINGS Carrie has $6000 to invest. She puts x dollars of this money into a savings account that earns 2% interest per year. She uses the rest of the money to purchase a certificate of deposit that earns 4% interest. Write an equation for the amount of money that Carrie will have in one year. ANSWER: T = 1.02x + 1.04(6000 − x) A P Find each sum or difference. 2 2 55. (7a − 5) + (−3a + 10) B Q ANSWER: 4a + 5 C R 2 D T ANSWER: D 53. SHORT RESPONSE For a science project, Jodi selected three bean plants of equal height. Then, for five days, she measured their heights in centimeters and plotted the values on the graph below. eSolutions Manual - Powered by Cognero 2 2 56. (8n − 2n ) + (4n − 6n ) ANSWER: 12n − 8n 2 3 2 3 2 57. (4 + n + 3n ) + (2n − 9n + 6) ANSWER: 3 2 3n − 6n + 10 2 2 58. (−4u − 9 + 2u) + (6u + 14 + 2u ) ANSWER: 2 Page 5 3 2 3 2 57. (4 + n + 3n ) + (2n − 9n + 6) ANSWER: 8-3 Multiplying Polynomials 3 2 3n − 6n + 10 2 2 58. (−4u − 9 + 2u) + (6u + 14 + 2u ) ANSWER: 2 −2u + 8u + 5 59. (b + 4) + (c + 3b − 2) ANSWER: 4b + c + 2 3 3 60. (3a − 6a) − (3a + 5a) ANSWER: −11a 3 3 2 61. (−4m − m + 10) − (3m + 3m − 7) ANSWER: 3 2 −7m − 3m − m + 17 62. (3a + 4ab + 3b) − (2b + 5a + 8ab) ANSWER: −2a − 4ab + b Simplify. 4 3 3 4 63. (−2t ) − 3(−2t ) ANSWER: 12 −56t 2 3 3 2 64. (−3h ) − 2(−h ) ANSWER: −29h 6 3 2 3 3 65. 2(−5y ) + (−3y ) ANSWER: 6 50y − 27y 9 4 2 2 2 66. 3(−6n ) + (−2n ) ANSWER: 8 108n + 4n 4 eSolutions Manual - Powered by Cognero Page 6