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Destinyyyy

  • one year ago

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  1. Destinyyyy
    • one year ago
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    Find the real solutions of the equation. 4x^2/3 -31x ^1/3 -8=0

  2. Destinyyyy
    • one year ago
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    @dinamix @freckles @Vocaloid

  3. Destinyyyy
    • one year ago
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    w= -1/4 w= 8

  4. Vocaloid
    • one year ago
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    hm, we can do another substitution to make the algebra a bit simpler let's let a = x^(1/3) that gives us 4a^2 - 31a - 8 which factors to (4a+1)(a-8) = 0 know where to go from here?

  5. Destinyyyy
    • one year ago
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    Yeah.. w= -1/4 w= 8

  6. Destinyyyy
    • one year ago
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    Then I got x= -1/16 and x= 512

  7. Destinyyyy
    • one year ago
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    But my answers are wrong so I messed up somewhere

  8. Destinyyyy
    • one year ago
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    x^ 2/3 = -1/4 x^1/3 =8

  9. Destinyyyy
    • one year ago
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    8*8*8= 512 x=512

  10. dinamix
    • one year ago
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    x^1/3 = -1/4 and x^1/3 = 8 thats only

  11. dinamix
    • one year ago
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    u have too find x

  12. Destinyyyy
    • one year ago
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    Yes I know that

  13. Destinyyyy
    • one year ago
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    The one x= 512

  14. Destinyyyy
    • one year ago
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    x= -1/4 ^3/2

  15. Destinyyyy
    • one year ago
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    4*4= 16 So is the answer -1/16 or -1/8 ???

  16. jim_thompson5910
    • one year ago
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    As dinamix is saying, you should have `x^1/3 = -1/4` and NOT `x^2/3 = -1/4` You let w = x^1/3, so if w = -1/4, then `x^1/3 = -1/4` solve x^1/3 = -1/4 for x

  17. dinamix
    • one year ago
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    x= -1/ 64

  18. Destinyyyy
    • one year ago
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    I figured that was a miss type... Why is 2/3 now 1/3???

  19. jim_thompson5910
    • one year ago
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    you made w = x^1/3 that allowed you to go from `4x^2/3 -31x ^1/3 -8=0` to `4w^2 - 31w - 8 = 0`

  20. jim_thompson5910
    • one year ago
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    solving 4w^2 - 31w - 8 = 0 gives w = -1/4 or w = 8

  21. dinamix
    • one year ago
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    cuz suppose a= x^1/3 not 2/3

  22. jim_thompson5910
    • one year ago
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    if w = x^1/3, then w^2 = x^2/3

  23. Destinyyyy
    • one year ago
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    Yes w= x^1/3 But w^2= x^2/3

  24. dinamix
    • one year ago
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    x=512 and x= -1/64

  25. jim_thompson5910
    • one year ago
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    the solutions w = -1/4 or w = 8 are for w and not for w^2

  26. Destinyyyy
    • one year ago
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    Yes thats what ive been saying

  27. Destinyyyy
    • one year ago
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    I have w solved already as 512.. Im now trying to solve w^2... How did you get 64 @dinamix

  28. Destinyyyy
    • one year ago
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    I thought I only times it 2 times not 3

  29. jim_thompson5910
    • one year ago
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    dinamix cubed both sides of x^1/3 = -1/4

  30. dinamix
    • one year ago
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    yup this so we find x=-1/64

  31. Destinyyyy
    • one year ago
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    I see okay

  32. Destinyyyy
    • one year ago
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    Last problem

  33. dinamix
    • one year ago
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    so sec u sould understand okey ?

  34. Destinyyyy
    • one year ago
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    I got this one wrong and Id like it checked before redoing number 13. (x-3)^2/3 =25

  35. Destinyyyy
    • one year ago
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    Yes I understand. Thank you

  36. dinamix
    • one year ago
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    a = (x-3)^1/3

  37. dinamix
    • one year ago
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    and will be a^2=25

  38. Destinyyyy
    • one year ago
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    My final answer was x= 128

  39. Destinyyyy
    • one year ago
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    But its wrong

  40. dinamix
    • one year ago
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    a=5 or a=-5

  41. Destinyyyy
    • one year ago
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    Whered you get the negative 5 from?? O.o

  42. dinamix
    • one year ago
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    hmm (-5)^2 = 25 right

  43. dinamix
    • one year ago
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    ?

  44. Destinyyyy
    • one year ago
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    Yes

  45. dinamix
    • one year ago
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    so u understand

  46. dinamix
    • one year ago
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    now

  47. Destinyyyy
    • one year ago
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    I get where -122 comes from.. But where did the -5 come from?

  48. dinamix
    • one year ago
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    x=128 and x=-122

  49. dinamix
    • one year ago
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    \[\frac{ 0\pm \sqrt{4*25} }{ 2 }\]

  50. dinamix
    • one year ago
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    a^2-25 = 0 u have to solve it u get 5 and -5

  51. dinamix
    • one year ago
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    @Destinyyyy

  52. Destinyyyy
    • one year ago
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    Ohhh.. I didnt do that. I just added 3 to 125 and thought I was done. So I have to put it into the qe okay

  53. Destinyyyy
    • one year ago
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    Okay.. Im starting the redo question

  54. dinamix
    • one year ago
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    ok i am going to sleep , i hope u understand

  55. Destinyyyy
    • one year ago
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    I believe I do..

  56. Destinyyyy
    • one year ago
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    New problem.. (x-5) ^2/3 =4

  57. Destinyyyy
    • one year ago
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    -3,13

  58. freckles
    • one year ago
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    oops @Destinyyyy I forgot to consider other real solution for that previous problem.

  59. Destinyyyy
    • one year ago
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    Its okay. I wrote a number wrong in the original problem

  60. Destinyyyy
    • one year ago
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    Finally im done and can take the quiz

  61. freckles
    • one year ago
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    good job

  62. Destinyyyy
    • one year ago
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    Thank you.. Do you mind checking my answers for the quiz in a new question?

  63. freckles
    • one year ago
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    ok sure

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