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thejoshfish

Solve the following system. 4x^2 + 9y^2 =72 x^2 - y^2 = 5 The solutions are?

  • one year ago
  • one year ago

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  1. thejoshfish
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    i've tried to do this at least 5 times. i don't understand it at all

    • one year ago
  2. mathslover
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    |dw:1337656235090:dw|

    • one year ago
  3. mathslover
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    |dw:1337656263685:dw|

    • one year ago
  4. mathslover
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    |dw:1337656308816:dw|

    • one year ago
  5. Outkast3r09
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    or multiply the second equation by -4

    • one year ago
  6. mathslover
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    |dw:1337656338440:dw|

    • one year ago
  7. mathslover
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    |dw:1337656365038:dw|

    • one year ago
  8. mathslover
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    |dw:1337656398578:dw|

    • one year ago
  9. Outkast3r09
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    \[4x^2+9y^2=72\] \[-4(x^2-y^2)=-4(5)\]

    • one year ago
  10. mathslover
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    |dw:1337656433069:dw|

    • one year ago
  11. thejoshfish
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    there's supposed to be 2 solutions: The solutions are: (_,_) & (_,_)

    • one year ago
  12. Outkast3r09
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    \[4x^2+9y^2=72\] \[-4x^2+4y^2=-20\] add them together to get \[13y^2=52\]

    • one year ago
  13. thejoshfish
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    trust me, i've gotten all the solutions possible. but the answer is still wrong.

    • one year ago
  14. Outkast3r09
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    \[y^2=\sqrt{\frac{52}{13}}\]

    • one year ago
  15. mathslover
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    the solutions are : sqrt(52/11) and sqrt(107/11)

    • one year ago
  16. thejoshfish
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    but there's 4 solutions.

    • one year ago
  17. mathslover
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    @ outkast i think y = sqrt(52/11) u wrote y^2 = sqrt(52/13) ?

    • one year ago
  18. Outkast3r09
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    yeah i think there might be aproblem with your's mine is correct i thinkkk let me check

    • one year ago
  19. Outkast3r09
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    yeah mine is correct .. by elimination

    • one year ago
  20. mathslover
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    u can write it as : |dw:1337656633671:dw|

    • one year ago
  21. radar
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    \[y=\pm2\]\[x=\pm3\]

    • one year ago
  22. thejoshfish
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    i also got that ^

    • one year ago
  23. Outkast3r09
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    i'ma cheat *grabs calculator

    • one year ago
  24. thejoshfish
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    lol, i've done that too! ^

    • one year ago
  25. Outkast3r09
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    ahh wait mathslover you have 7 instead of 9

    • one year ago
  26. mathslover
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    hey sorry , i took 4x^2 + 7y^2 but it is 4x^2 + 9y^2 , therefore the 4 solutions are : |dw:1337656820684:dw|

    • one year ago
  27. Outkast3r09
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    i believe you made a 9 really badly and thought it was a 7 the first equation is 4x^2+9y^2=72

    • one year ago
  28. brinethery
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    For y, I got y= +/- sqrt (52/13)

    • one year ago
  29. Outkast3r09
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    thats right now for x

    • one year ago
  30. mathslover
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    yes sorry , y = + 2 , -2 x = +3 , -3

    • one year ago
  31. mathslover
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    @Outkast3r09 x = +3 , -3 right ?

    • one year ago
  32. Outkast3r09
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    \[x^2-(2^2)=5\] \[x^2-(-2^2)=5\]

    • one year ago
  33. brinethery
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    x = +/- 3

    • one year ago
  34. Outkast3r09
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    \[x^2-4=5\] \[x^2-4=5\]

    • one year ago
  35. radar
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    \[\sqrt{52/13}=\pm2\]\[x ^{2}=9\]\[x=\pm3\]

    • one year ago
  36. brinethery
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    I was slow, I was using a crappy calculator.

    • one year ago
  37. Outkast3r09
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    does this mean it's a multiplicity of 2?

    • one year ago
  38. brinethery
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    @thejoshfish did you try putting in y= +/- sqrt (52/13) and x=+/- 3?

    • one year ago
  39. brinethery
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    @Outkast3r09 it means 3*3 and (-3)(-3).

    • one year ago
  40. thejoshfish
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    i sure did. haha trust me, i tried everything. i'm so fed up. but you guys are wonderful.

    • one year ago
  41. Outkast3r09
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    those are your answers are you using like owl or whatever

    • one year ago
  42. thejoshfish
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    owl?

    • one year ago
  43. brinethery
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    Talk with your instructor. I'm taking statics and have the instructor's manual. They're wrong way more times than I'd like them to be. I think the grad students who write the manuals aren't getting enough sleep.

    • one year ago
  44. Outkast3r09
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    Online web learning

    • one year ago
  45. Outkast3r09
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    what does it say the answers are josh?

    • one year ago
  46. thejoshfish
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    alpha omega academy

    • one year ago
  47. thejoshfish
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    it doesn't tell me. but thanks for helping.

    • one year ago
  48. Outkast3r09
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    sometimes those sites have like a function button with like +- and what not . that could be the problem or try 3,-3 , -2 ,2

    • one year ago
  49. brinethery
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    If you have to take the higher level physics series, they might make you use MasteringPhysics. Have fun with that! Groans.

    • one year ago
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