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charlotteakina

  • 2 years ago

Help!? PLEASE! Screenshot attached! 2 questions! 1 question answered! ONE TO GO!

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  1. Coolsector
    • 2 years ago
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    5 people means 3.6 seconds so y people will be t seconds we can show it this way : |dw:1350566474324:dw|

  2. Coolsector
    • 2 years ago
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    now cross multiply and get the connection between y (number of people) and t (seconds)

  3. Coolsector
    • 2 years ago
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    and hey .. how are you ? :)

  4. Decart
    • 2 years ago
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    \[t=.72p\]

  5. Coolsector
    • 2 years ago
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    |dw:1350566721091:dw|

  6. Coolsector
    • 2 years ago
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    if you multiply one side by 100 you should multiply the other by 100 too

  7. Coolsector
    • 2 years ago
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    we need to isolate t from the equation that i gave you

  8. Coolsector
    • 2 years ago
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    no .. it's final answer is correct but i want you to be able to get it by yourself

  9. Coolsector
    • 2 years ago
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    there is no 75 in decart's answer :|

  10. Coolsector
    • 2 years ago
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    \[\frac{ 5 }{ y } = \frac{ 3.6 }{ t }\] multiply both sides by \[y \times t\] we get: \[5t = 3.6y\] now divide both sides of the equation by 5 we get: \[t = \frac{ 3.6 }{ 5 } \times y\] which is the same as \[t=0.72y\]

  11. Coolsector
    • 2 years ago
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    yes sorry i was washing dishes lol

  12. Coolsector
    • 2 years ago
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    division of two fractions is like multiplying the first by the reciprocal of the second

  13. Coolsector
    • 2 years ago
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    \[\frac{ a }{ b } \div \frac{ c }{ d } = \frac{ a }{ b } \times \frac{ d }{ c }\]

  14. Coolsector
    • 2 years ago
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    so you can rewrite the problem as .. ?

  15. Coolsector
    • 2 years ago
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    no i just gave an example

  16. Coolsector
    • 2 years ago
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    you have to multiply the first fraction by the reciprocal of the second..

  17. Coolsector
    • 2 years ago
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    |dw:1350568226013:dw|

  18. Coolsector
    • 2 years ago
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    yes .. and changed the division to multiplication this his how you divide two fractions..

  19. Coolsector
    • 2 years ago
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    \[\frac{ (x^2-x-6)(x^2+5x+4) }{ (x^2-2x-3)(x^2+x-12) }\]

  20. Coolsector
    • 2 years ago
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    this is now what you have to simplify "so, do I multiply x^2 + x - 12 by x^2 + 5x + 4 now? " no.. why you say that ?

  21. Coolsector
    • 2 years ago
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    \[\frac{ a }{ b } \neq a * b\]

  22. Coolsector
    • 2 years ago
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    we changed the division to multiplication because we divided FRACTION BY FRACTION

  23. Coolsector
    • 2 years ago
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    no it's not right

  24. Coolsector
    • 2 years ago
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    \[\frac{ 5 }{ 3 } * \frac{ 4 }{ 2 } = ?\]

  25. Coolsector
    • 2 years ago
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    solve this please

  26. Coolsector
    • 2 years ago
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    right you just multiplied 5 with 4 and divided by the multiplication of 3 with 2

  27. Coolsector
    • 2 years ago
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    |dw:1350569102823:dw|

  28. Coolsector
    • 2 years ago
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    so same here .. after we changed the division into multiplication it's just multiplication of two fractions

  29. Coolsector
    • 2 years ago
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    you tell me .. how do we multiply those two fractions ?

  30. Coolsector
    • 2 years ago
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    i wont get mad why would i :| look : \[\frac{ x^2-x-6 }{ x^2-2x-3 } \times \frac{ x^2+5x+4 }{ x^2+x-12 } = \frac{ (x^2-x-6)(x^2+5x+4) }{ (x^2-2x-3)(x^2+x-12) }\]

  31. Coolsector
    • 2 years ago
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    i dont know why you multiply numerator by denominator

  32. Coolsector
    • 2 years ago
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    this is what you get after the multiplication of the two fractions now we better factor every term than open the brackes like x^2-x-6 = x^2-3x+2x-6 = x(x-3)+2(x-3) = (x+2)(x-3)

  33. Coolsector
    • 2 years ago
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    yes look : whenever there is multiplication of two fractions you multiply numerator by numerator and denom by denom.. whenever there is division of two fractions you keep the first fraction as it is you change the division into multiplication but then for the second fraction you flip numerator and denominator and then you have multiplication of two fractions..

  34. Coolsector
    • 2 years ago
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    yes as i wrote up there

  35. LCK
    • 2 years ago
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    I'll just to butt in for a bit, the general flow of fraction division goes like this: 1. Turn the division into a multiplication by inverting the second fraction 2. Factorise as much as possible and eliminate common terms. 3. Solve by multiplying the numerator by the numerator and denominator by denominator. Yes I wrote the same thing as cool sorry :/.

  36. Coolsector
    • 2 years ago
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    now it's better to factor every term than open the brackets .. so factoring x^2-x-6 gives = x^2-3x+2x-6 = x(x-3)+2(x-3) = (x+2)(x-3)

  37. Coolsector
    • 2 years ago
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    can you factor the rest of the terms ?

  38. Coolsector
    • 2 years ago
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    yes.. i just showed the way

  39. Coolsector
    • 2 years ago
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    you see my last expression is (x+2)(x-3)

  40. Coolsector
    • 2 years ago
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    now factor the rest of the terms .. what do you get ?

  41. Coolsector
    • 2 years ago
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    so are you factoring the rest ?

  42. Coolsector
    • 2 years ago
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    good so how the expression looks like ?

  43. Coolsector
    • 2 years ago
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    after you change every term by it's factored form

  44. Coolsector
    • 2 years ago
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    you have to replace every term by it's factored from like replaceing " x^2 - x- 6" by " (x+2)(x-3) " in the last expression

  45. Coolsector
    • 2 years ago
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    very good

  46. Coolsector
    • 2 years ago
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    now you can eliminate some of them..

  47. Coolsector
    • 2 years ago
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    if you have the same thing in the numerator and in the denominator you can eliminate it ..

  48. Coolsector
    • 2 years ago
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    and one more ..

  49. Coolsector
    • 2 years ago
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    |dw:1350571449666:dw|

  50. Coolsector
    • 2 years ago
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    so what is left .. \[\frac{ x+2 }{ x-3 }\]

  51. Coolsector
    • 2 years ago
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    yes

  52. Coolsector
    • 2 years ago
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    yw :)

  53. Coolsector
    • 2 years ago
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    i hope the next question of this kind will be easier for you now that you know the steps

  54. Coolsector
    • 2 years ago
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    Im happy i could help you

  55. Coolsector
    • 2 years ago
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    :)

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