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Thread: help

  1. #1
    Newbie
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    help

    can some one show me how to do this problem

    negative four times the sum of n and seven is equal to negative five times n minus nine
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by jim1174
    can some one show me how to do this problem

    negative four times the sum of n and seven is equal to negative five times n minus nine
    Translated into an equation this is:

    $\displaystyle
    (-4)(n+7)=(-5)(n-9)
    $

    Multiply both sides of the equation by $\displaystyle -1/4$, and as
    a "-" times a "-" is a "+" this gives:

    $\displaystyle
    n+7=(5/4)(n-9)
    $

    Now expand the brackets on the Right Hand Side of the equation:

    $\displaystyle
    n+7=\frac{5}{4}n-\frac{45}{4}
    $

    Add 45/4 to both sides of the equation:

    $\displaystyle
    n+\frac{73}{4}=\frac{5}{4}n
    $.

    Subtract $\displaystyle n$ from both sides:

    $\displaystyle
    \frac{73}{4}=\frac{1}{4}n
    $.

    Finlay multiply both sides by 4:

    $\displaystyle
    73=n
    $,

    so $\displaystyle n=73$

    RonL
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