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Homework Help: Algebra expression problem

  1. Mar 17, 2010 #1

    I have:

    [tex] \frac{a}{b+a+s} + \frac{c*b}{(b+a+s)(c+s)}[/tex]

    I can rearrange that to:

    [tex]\frac{a-c}{b+a-c} * \frac{b+a}{b+a+s} + \frac{b}{b+a-c} * \frac{c}{c+s} [/tex]

    Is this correct? If so, can someone tell me why the +s changes into a -c?
  2. jcsd
  3. Mar 17, 2010 #2


    User Avatar
    Science Advisor

    You should supply the steps. Also what are you trying to achieve?
    A simpler expression is (ac + as + bc)/[(b + a + s)(c + s)].
  4. Mar 17, 2010 #3


    Staff: Mentor

    If your goal is to combine the two rational expressions, multiply the one on the left by 1 in the form of (c + s)/(c + s). That gives you the same denominator in both expressions, so you can then add the numerators.

    A +s should not change to a -c.
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