Algebra 1 Common Core Student Edition, Grade 8-9

(Marvins-Underground-K-12) #1
Ex e r c i se s 7. —1.5, -1 9. - 3 , 1.25 11. - §, y


  1. -11, 4f 15. -2.6, 12 17. -2.56, 0.16

  2. -0.47, 1.34 21. -2.26, 0.59 23. Quadratic
    formula, completing the square, or graphing; the
    coefficient of the x2-term is 1 , but the equation cannot be
    factored. 25. Quadratic formula, graphing; the equation
    cannot be factored. 27. Factoring; the equation is easily
    factorable. 29.0 31.0 33.2 35. ±4 37. ±1.73

  3. 2 41. No, there are no real-number solutions of the
    equation (14 - x)(50 + 5x) = 750. 43. Find values of a,
    b, and c such that b2 - 4ac > 0. 45a. 16; 1, 5
    b. 81; - 5 , 4 c. 73; -0 .3 9 , 3.89 d. Rational; if the
    discriminant is a perfect square, then its square root is an
    integer, and the solutions are rational. 47. never

  4. always 51. 1 53. G 55. 1.54, 8.46

  5. -2, -1 57. -6.06, 0.06

  6. (1, -3 2 4 ) 23. (-1, -29) 25. -1.65, 3.65

  7. -1.96, 2.56 29. -7, 1 31. about 13.3
    33a. 75-2w b. 11.6 ft or 25.9 ft c. 51.9 ft or 23.1 ft

  8. no solution 37. 2.27, 5.73 39. no solution

  9. -0 .1 1 , 9.11 43. She forgot to divide each side by 4 to
    make the coefficient of the x2-term 1.

  10. -0.45, 4.45 49a. 3 ± V 5 b. (3, - 5 ) c. Answers
    will vary. Sample: p is the x-coordinate of the vertex and
    -q is the y-coordinate of the vertex. 51. 0.0215 53. 2

  11. 4.5 57. - 6 , - 5 58. ± | 59. §

  12. m 12 61.-1 62. f 13 63. y 29 64.81 65.0 6 6 .- 1 5


Lesson 9-6 pp. 582-588
Go t It? 1. -3, 7 2. 144.8 ft 3a. Factoring; the
equation is easily factorable, b. Square roots; there is no
x-term. c. Quadratic formula, graphing; the equation
cannot be factored. 4a. 2 b. 2; if a > 0 and c < 0, then



  • 4 a c > 0 and b2 - 4ac > 0.
    Lesso n Ch eck 1. -4, | 2. -0 .9 4 , 1.22 3. 2 4. If t h e
    discriminant is positive, there are 2 x-intercepts. If the
    discriminant is 0, there is 1 x-intercept. If the discriminant
    is negative, there are no x-intercepts. 5. Factoring
    because the equation is easily factorable; quadratic
    formula or graphing because the equation cannot be
    factored. 6. If you complete the square for
    ax2 + bx + c = 0 , you will get the quadratic formula.










Lesson 9-7
Go t It?
1 a.

pp. 589-594

/]y


X


  • ( «'o


b.

exponential

y
I

•s
0 X

quae ratic


  1. exponential 3. Answers will vary. Sample: linear;
    y = 480.7x+ 18,252.4
    Lesso n Ch eck 1. quadratic 2. linear 3. exponential

  2. No, a function cannot be both linear and exponential.
    5. Graph the points, or test ordered data for a common
    difference (linear function), a common ratio (exponential
    function), or a common second difference (quadratic
    function).
    Ex e r c i se s
    y
    A
    X
    0! L


y
(|

0 X
—■

linear quadratic


  1. linear

  2. quadratic; y = 3x 2

  3. linear; y = - 0 .5 x + 2

  4. exponential;
    y = 540(1.03)*


21b. The second common difference is twice the
coefficient of the x 2 -term. c. When second differences
are the same, the data are quadratic. The coefficient
of the x2-term is one-half the second difference.

y

X
—■ O

linear
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