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Math Help - Changing the subject question help!

  1. #1
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    Changing the subject question help!

    I need to make a the subject, but i keep ending up with 0 a's. Can someone please give a step by step to how they did it if they know the answer.

    And thankyou to anyone in advanced.

    b = (a + x) / (a + c)


    edit: the right side is meant to be a fraction, but the best way i can think of writing is is with a '/'.
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  2. #2
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    Quote Originally Posted by nugiboy View Post
    I need to make a the subject, but i keep ending up with 0 a's. Can someone please give a step by step to how they did it if they know the answer.

    And thankyou to anyone in advanced.

    b = (a + x) / (a + c)


    edit: the right side is meant to be a fraction, but the best way i can think of writing is is with a '/'.
    b = \frac{a + x}{a + c}

    b(a + c) = a + x

    ab + bc = a + x

    ab - a = x - bc

    a(b - 1) = x - bc

    a = \frac{x - bc}{b - 1}

    Of course, we need to recall that a \neq -c else the original expression can't exist.

    -Dan
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  3. #3
    Grand Panjandrum
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    Quote Originally Posted by nugiboy View Post
    I need to make a the subject, but i keep ending up with 0 a's. Can someone please give a step by step to how they did it if they know the answer.

    And thankyou to anyone in advanced.

    b = (a + x) / (a + c)


    edit: the right side is meant to be a fraction, but the best way i can think of writing is is with a '/'.
    <br />
b=\frac{a+x}{a+c}<br />

    So:

    <br />
(a+c)b=a+x<br />

    or:

    <br />
(b-1)a=x-cb<br />

    so:

    <br />
a=\frac{x-cb}{b-1}<br />

    RonL
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