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-   -   Transposition of formulae (https://www.askmehelpdesk.com/showthread.php?t=414571)

  • Nov 10, 2009, 02:13 AM
    emma51
    transposition of formulae
    please could someone help me answer this question??

    y= 900a /
    2 + a
  • Nov 10, 2009, 03:24 AM
    Unknown008

    Do you want to make 'a' the subject of formula?
  • Nov 10, 2009, 04:19 AM
    emma51
    Yes
  • Nov 10, 2009, 04:21 AM
    Unknown008

    Ok, I'll tell you to multiply each side by a+2 first and let's see what you get.

    I'll be guiding you till the answer. :)
  • Nov 10, 2009, 05:35 AM
    emma51
    THIS IS WHAT I GOT

    2y + ay +900a
    2y + 900a - ay
    2y= (900-y)a
    a= 2y/900-y

    = 2y/900-2y/y
    = y/450-2

    this is the answer I got
  • Nov 10, 2009, 05:59 AM
    Perito
    2y + ay = 900a

    2y = 900a - ay

    Watch your "=" signs.

    2y= (900-y)a



    So far, so good. "a" is now the subject of the expression.

    This is wrong. You can't simply put the numerator over each element of the denominator.





    You could do this:





    but I'm not sure why you'd want to do that.
  • Nov 10, 2009, 06:51 AM
    Unknown008

    Yes, leave it as that's fine.
  • Nov 11, 2009, 02:12 AM
    emma51
    I did the equation like that as the question was:

    A major chemical company researching crop yields tries out a new pesticide. The results indicate that, per hectare, for a kg of pesticide the extra yield y kg of a crop is given by the equation

    the question was:

    what is the formula which gives the amount, a kg, of pesticide needed to return and extra yield of y kg?
  • Nov 11, 2009, 03:04 AM
    Unknown008

    Yes, you leave it as said previously. :)
  • Nov 11, 2009, 04:53 AM
    emma51
    Thanks for your help :)
  • Nov 11, 2009, 06:14 AM
    Unknown008

    You're welcome! :)

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