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Math Help - Solving

  1. #1
    Member GAdams's Avatar
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    Solving

    I need to solve this for b

    Here's what I got so far:

    a(a-b) = 3s(3s+b)

    a^2 - ab = 9s^2 + 3sb

    divide it all by a

    a^2/ a - ab/a = 9s^2/a + 3sb/a

    gives

    a - b = 9s^s/a + 3sb/a

    -b = 9s^s/a + 3sb/a -a

    ....not sure what to do about that b in 3sb?

    Thanks
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  2. #2
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by GAdams View Post
    I need to solve this for b

    Here's what I got so far:

    a(a-b) = 3s(3s+b)

    a^2 - ab = 9s^2 + 3sb
    Keep it up to this point.

    Now get all the b terms on one side and everything else on the other:
    -ab - 3sb = 9s^2 - a^2

    Note the the LHS factors:
    b(-a - 3s) = 9s^2 - a^2

    You take it from here.

    -Dan
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  3. #3
    MHF Contributor
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    The idea is to isolate b alone by itself in the lefthand side.

    After your second line, collect all the b-terms at the lefthand side, factor out the b, etc,

    Umm, let me continue...

    a(a-b) = 3s(3s+b)

    a^2 - ab = 9s^2 + 3sb


    -ab -3sb = 9s^2 -a^2
    b(-a -3s) = 9s^2 -a^2
    b(-(3s +a)) = (3s +a)(3s -a)
    Divide both sides by -(3s +a),
    b = -(3s -a)
    b = a -3s ---------------------------answer.
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