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anonymous

  • one year ago

Solve the problem, If f(x)= x-3A/3x+5 and f(3)=6. what is the value of A?

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  1. anonymous
    • one year ago
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    @jim_thompson5910

  2. jim_thompson5910
    • one year ago
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    this is f(x), right? \[\Large f(x) = \frac{x-3A}{3x+5}\]

  3. anonymous
    • one year ago
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    Correct

  4. jim_thompson5910
    • one year ago
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    \[\Large f(x) = \frac{x-3A}{3x+5}\] \[\Large f(3) = \frac{3-3A}{3(3)+5}\] \[\Large 6 = \frac{3-3A}{3(3)+5}\] \[\Large 6 = \frac{3-3A}{14}\] \[\Large 14*6 = 14*\frac{3-3A}{14}\] \[\Large 84 = 3-3A\] \[\Large A = ??\]

  5. jim_thompson5910
    • one year ago
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    In step 2, I replaced every x with 3 In step 3, I replaced f(3) with 6 (since f(3) = 6)

  6. anonymous
    • one year ago
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    Okay so I got A= -27

  7. anonymous
    • one year ago
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    |dw:1433980377815:dw|

  8. anonymous
    • one year ago
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    Use the accompanying graph of y=f(x) to sketch the graph of the indicated equation. Graph one transformation in each coordinate system.

  9. anonymous
    • one year ago
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    @jim_thompson5910

  10. jim_thompson5910
    • one year ago
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    f(-x) means you reflect over the y axis 2*f(-x) means you scale vertically, or stretch vertically, by a factor of 2

  11. anonymous
    • one year ago
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    How would I show this on the coordinate plane?

  12. jim_thompson5910
    • one year ago
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    start by reflecting each point over the y axis

  13. anonymous
    • one year ago
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    so it would be (-2,-2) and then? what?

  14. jim_thompson5910
    • one year ago
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    do the same for the other points as well

  15. jim_thompson5910
    • one year ago
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    |dw:1433981229533:dw|

  16. jim_thompson5910
    • one year ago
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    |dw:1433981248199:dw|

  17. jim_thompson5910
    • one year ago
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    imagine this happens to all of the points

  18. jim_thompson5910
    • one year ago
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    you'd get something like this |dw:1433981278828:dw|

  19. anonymous
    • one year ago
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    Okay :)

  20. anonymous
    • one year ago
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    and then? how would I do the second part?

  21. jim_thompson5910
    • one year ago
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    the 2* out front means you double each y coordinate

  22. jim_thompson5910
    • one year ago
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    ex: (2,-2) ----> (2,-4)

  23. jim_thompson5910
    • one year ago
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    ex: (2,-2) ----> (2,-4) |dw:1433981434340:dw| imagine this happens to EVERY point

  24. anonymous
    • one year ago
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    so I would show this for each point!

  25. jim_thompson5910
    • one year ago
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    yes

  26. jim_thompson5910
    • one year ago
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    and the overall graph

  27. anonymous
    • one year ago
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    Alright awesome thank you!

  28. anonymous
    • one year ago
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    ONe quick question

  29. anonymous
    • one year ago
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    Before you leave! :)

  30. anonymous
    • one year ago
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    If they ask me for which of the following values of x does f(x)=-20 and the graph is showing :|dw:1433981600730:dw|

  31. jim_thompson5910
    • one year ago
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    draw a horizontal line through y = -20 |dw:1433981843252:dw|

  32. jim_thompson5910
    • one year ago
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    then determine where that horizontal line crosses the curve

  33. anonymous
    • one year ago
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    (-25,15), (-15,0), (0,-15) , (10,-20) , (15,-10), (20,10) and (25,0)

  34. anonymous
    • one year ago
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    those are the points they provide!

  35. anonymous
    • one year ago
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    I know that -20 and 10 both have f(x)=-20

  36. jim_thompson5910
    • one year ago
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    hint: y = f(x)

  37. anonymous
    • one year ago
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    How would I determine the answer?

  38. anonymous
    • one year ago
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    @jim_thompson5910

  39. jim_thompson5910
    • one year ago
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    another hint: each point is of the form (x,y)

  40. anonymous
    • one year ago
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    Would I say {-20,10}

  41. anonymous
    • one year ago
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    This is all I could think of!

  42. jim_thompson5910
    • one year ago
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    (-20,10) means x = -20

  43. jim_thompson5910
    • one year ago
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    but they say f(x) = -20

  44. anonymous
    • one year ago
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    OKAY,,,, maybe I put it wrong? (-20,-20) and (10,-20)

  45. jim_thompson5910
    • one year ago
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    just look through the points (-25,15), (-15,0), (0,-15) , (10,-20) , (15,-10), (20,10) and (25,0) where the y coord is -20

  46. jim_thompson5910
    • one year ago
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    y = f(x) f(x) = -20 y = -20

  47. anonymous
    • one year ago
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    Okay so all I would say is (10,-20) correct?

  48. anonymous
    • one year ago
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    @jim_thompson5910

  49. jim_thompson5910
    • one year ago
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    yes that is the only point that fits the description

  50. anonymous
    • one year ago
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    okay... and sorry one last thing I PROMISE!!!

  51. anonymous
    • one year ago
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    iF I HAVE THE SAME coordinate plane but with different points and it is 20 instead of 25 and they ask for what numbers x is f(x)<0?

  52. anonymous
    • one year ago
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    How would I write this?

  53. anonymous
    • one year ago
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    It starts with -12 I know this but would it be [-12,-1]

  54. anonymous
    • one year ago
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    @jim_thompson5910

  55. jim_thompson5910
    • one year ago
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    can you post a screenshot of the full problem?

  56. anonymous
    • one year ago
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    |dw:1433982828860:dw|

  57. anonymous
    • one year ago
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    The graph of a function f is given. Use the graph to answer the question. (-20,12) , (-12,0) , (0,-12) , (8,-16) , (12, -8), (16,8) and (20,0)

  58. anonymous
    • one year ago
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    For what numbers x is f(x)<0 ?

  59. jim_thompson5910
    • one year ago
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    look at the points where the y coord is negative

  60. jim_thompson5910
    • one year ago
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    |dw:1433983055819:dw|

  61. anonymous
    • one year ago
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    Okay and they cant be greater than 0 correct?

  62. jim_thompson5910
    • one year ago
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    yeah because you said f(x) < 0

  63. anonymous
    • one year ago
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    Right so how would I say this?

  64. jim_thompson5910
    • one year ago
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    they just want you to list points?

  65. anonymous
    • one year ago
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    OKay so in this case it would be (-12,0)

  66. jim_thompson5910
    • one year ago
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    if that's the case, then list any points with y coordinates less than 0

  67. anonymous
    • one year ago
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    It asks me For what numbers x is f(x)<0

  68. jim_thompson5910
    • one year ago
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    what are the x intercepts of that graph

  69. anonymous
    • one year ago
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    -20 , -16, -12, -8, -4,0 4, 8, 12, 16 and 20

  70. jim_thompson5910
    • one year ago
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    |dw:1433983321114:dw|

  71. anonymous
    • one year ago
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    on the far left its -12 and on the far right its probably 14 because its in between 12 and 16

  72. jim_thompson5910
    • one year ago
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    |dw:1433983408801:dw|

  73. anonymous
    • one year ago
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    yes

  74. jim_thompson5910
    • one year ago
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    |dw:1433983425459:dw|

  75. jim_thompson5910
    • one year ago
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    |dw:1433983449734:dw|

  76. anonymous
    • one year ago
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    ok

  77. anonymous
    • one year ago
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    @jim_thompson5910

  78. anonymous
    • one year ago
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    ???

  79. anonymous
    • one year ago
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    @jim_thompson5910 how would I write this?

  80. anonymous
    • one year ago
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    @jim_thompson5910

  81. jim_thompson5910
    • one year ago
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    I think they just want the x values that correspond to when y is negative

  82. anonymous
    • one year ago
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    So would I write something like [-12, -1]

  83. jim_thompson5910
    • one year ago
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    where are you getting -1?

  84. anonymous
    • one year ago
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    idk? I am guessing that this is correct? but I have no clue

  85. anonymous
    • one year ago
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    [-12, 14]

  86. jim_thompson5910
    • one year ago
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    the x intercepts are -12 and 14 the interval (-12,14) represents the region when f(x) < 0

  87. anonymous
    • one year ago
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    OKay thank you! but wouldnt it have to be [ instead of ( ?

  88. jim_thompson5910
    • one year ago
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    () because you don't include the points on the x axis

  89. jim_thompson5910
    • one year ago
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    not [ ]

  90. anonymous
    • one year ago
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    OKay I got cha awesome thank you so so so much your amazing :D

  91. jim_thompson5910
    • one year ago
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    yw

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