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anonymous

  • 5 years ago

I want to know if i am rite 4. The total consumption of fossil fuels in the United States per year can be represented by the function C(x) = 0.0439x3 – 1.4911x2 + 14.224x + 41.76, where x is the number of years after 1970, and C(x) represents the amount of energy consumed in quadrillions of BTUs (or “quads”). In 1979, the U.S. consumed 81 quads of energy. Subtract C(x) – 81 and write down the resulting function. Since you know that 9 is a root of this function, find the other two roots. In what year after 1979 did the U.S. consumption of energy also reach 81 quads?

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  1. anonymous
    • 5 years ago
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    looks good to me. want the computation?

  2. anonymous
    • 5 years ago
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    can you work this problem out?

  3. anonymous
    • 5 years ago
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    well except it is not what i get

  4. anonymous
    • 5 years ago
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    bare with me, i going write i have so far

  5. anonymous
    • 5 years ago
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    let me try again and make sure i have it correct

  6. anonymous
    • 5 years ago
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    C(x) = 0.0439x3 – 1.4911x2 + 14.224x + 41.76

  7. anonymous
    • 5 years ago
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    so what you do is, substract 81 from 41.79

  8. anonymous
    • 5 years ago
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    \[C(x)=.0439x^3-1.4991x^2+14.224x+41.76\] is that right?

  9. anonymous
    • 5 years ago
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    i mean before you subtract is that correct?

  10. anonymous
    • 5 years ago
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    you going have c(c) 0.0439x^3-1.4911x^2+14.224-39.28 now you use syntethic divicion, we know 9 is a root of this function

  11. anonymous
    • 5 years ago
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    yes that would be correct. if C(9) = 81

  12. anonymous
    • 5 years ago
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    9] 0.0439 -1.4911 +14.224 -39.28

  13. anonymous
    • 5 years ago
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    but it doesn't seem to be according to my calculation let me check again

  14. anonymous
    • 5 years ago
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    no the first question

  15. anonymous
    • 5 years ago
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    when you do syntethic division, you get 0

  16. anonymous
    • 5 years ago
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    then you are correct!

  17. anonymous
    • 5 years ago
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    and teh giving you an extreme equation, and know you can find both root, 0.0439^2-1.096x+8.36

  18. anonymous
    • 5 years ago
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    you did the syntethinc division, and you got 0, correct?

  19. anonymous
    • 5 years ago
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    you did the syntethinc division, and you got 0, correct?

  20. anonymous
    • 5 years ago
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    you did the syntethinc division, and you got 0, correct?

  21. anonymous
    • 5 years ago
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    must be typing something in wrong because i do not get zero

  22. anonymous
    • 5 years ago
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    ok , type what you doing

  23. anonymous
    • 5 years ago
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    close, but i get C(9)=-.04 but that is probably close enough. you get 0 exactly?

  24. anonymous
    • 5 years ago
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    so you get 0?

  25. anonymous
    • 5 years ago
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    close to 0 , is not enough..

  26. anonymous
    • 5 years ago
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    ooho i see

  27. anonymous
    • 5 years ago
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    41.76-81=-39.24 not -39.28

  28. anonymous
    • 5 years ago
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    le't try it again, 9] 0.0439 -1.4911 +14.224 +39.28

  29. anonymous
    • 5 years ago
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    last number should be 39.24

  30. anonymous
    • 5 years ago
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    use your calculator, i dont knohere mine is

  31. anonymous
    • 5 years ago
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    then it will work

  32. anonymous
    • 5 years ago
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    i did and it works

  33. anonymous
    • 5 years ago
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    oh good, oh graph, yeah is -39.24, i thought it was an 8

  34. anonymous
    • 5 years ago
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    whew. then you get 0 i checked already

  35. anonymous
    • 5 years ago
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    get \[0.04390*x^2-1.096x+4.36\]

  36. anonymous
    • 5 years ago
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    yeah, now what, guadratic formula?

  37. anonymous
    • 5 years ago
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    yes what a pain. hold on and i will cheat if you like

  38. anonymous
    • 5 years ago
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    lol

  39. anonymous
    • 5 years ago
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    ikr, better then factoring at least...

  40. anonymous
    • 5 years ago
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    looks like x=20 or x = 4.966 rounded

  41. anonymous
    • 5 years ago
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    a miracle. 20 is exact!

  42. anonymous
    • 5 years ago
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    so going back to the problem, those are the root, you did quadratic formula?lol

  43. anonymous
    • 5 years ago
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    we must bei n the right tract

  44. anonymous
    • 5 years ago
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    so it must factor as \[(x-20)(.0439x-.218)\]

  45. anonymous
    • 5 years ago
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    no i didn't use the quadratic formula because i would have no patience for that

  46. anonymous
    • 5 years ago
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    i used maple

  47. anonymous
    • 5 years ago
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    lol, so wee know both root that were missing, the is really the aswner?

  48. anonymous
    • 5 years ago
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    yup that is it

  49. anonymous
    • 5 years ago
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    just changing them to word, and the will do it, thx man.

  50. anonymous
    • 5 years ago
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    must be. you can check easily (more or less) that 20 is a zero of \[.0439x^2-1.096x+4.36\] so as you know it must factor as \[(x-20)(something)\] and you have no choice for the something

  51. anonymous
    • 5 years ago
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    good luck

  52. anonymous
    • 5 years ago
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    oh crap, we are not,done, remember it ask you in qhat yesterday,

  53. anonymous
    • 5 years ago
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    oh crap, we are not,done, remember it ask you in qhat yesterday,

  54. anonymous
    • 5 years ago
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    oh crap, we are not,done, remember it ask you in qhat yesterday,

  55. anonymous
    • 5 years ago
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    oh crap, we are not,done, remember it ask you in qhat yesterday,

  56. anonymous
    • 5 years ago
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    oh crap, we are not,done, remember it ask you in qhat yesterday,

  57. anonymous
    • 5 years ago
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    lol, lagg, year*

  58. anonymous
    • 5 years ago
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    lol, lagg, year*

  59. anonymous
    • 5 years ago
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    you still here?

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