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Math Help - Forming an equation

  1. #1
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    Forming an equation (solved)

    A Music Store sells sets of CDs of equal value for $18.
    I) Taking x to be the number of Cds in each set, write down an expression in x to represent the price of each CD.

    The store reduces the number of Cds in each set by 3 and reduces the price in each set by $6.
    II) Write down an expression in x to represent the new price of each Cd in a set

    The Price in this case, has increased by $1
    iii) write and equation to represent the above info and solve for x.

    The answer I got for (i) was 18/x and (ii) x-3/12,

    But then at part three would it be 18/x = x-3/13
    or something like 18/x = x-3/12 + 1


    edit: Solved it, I put x-3/12 = 18/x + 1 and then after working that out I got -9 and 6, and since the answer cant be minus, I got $6
    Last edited by ZettaDigit; March 17th 2010 at 02:45 PM. Reason: solved it YAY
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  2. #2
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    forming an equation

    Quote Originally Posted by ZettaDigit View Post
    A Music Store sells sets of CDs of equal value for $18.
    I) Taking x to be the number of Cds in each set, write down an expression in x to represent the price of each CD.

    The store reduces the number of Cds in each set by 3 and reduces the price in each set by $6.
    II) Write down an expression in x to represent the new price of each Cd in a set

    The Price in this case, has increased by $1
    iii) write and equation to represent the above info and solve for x.

    The answer I got for (i) was 18/x and (ii) x-3/12,

    But then at part three would it be 18/x = x-3/13
    or something like 18/x = x-3/12 + 1


    edit: Solved it, I put x-3/12 = 18/x + 1 and then after working that out I got -9 and 6, and since the answer cant be minus, I got $6


    Your answer is correct. If you solved the quadratic equation which results you should show it in normal form Ax^2 + Bx +C =0 I think you have an error in part 2


    bjh
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