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Homework Help: Simple algebra: show that

  1. Oct 22, 2008 #1
    show that:
    a-a(1-a)a + a1-a(1-a)a-1
    can be written as:

    a-a(1-a)a-1



    3. The attempt at a solution

    a-a(1-a)a + a1-a(1-a)a-1

    a-a(1-a)a + a1a-a(1-a)a(1-a)-1

    a-a(1-a)a( 1 + a(1-a)-1)
     
  2. jcsd
  3. Oct 22, 2008 #2

    danago

    User Avatar
    Gold Member

    In your third line of working, instead of taking out a factor of (1-a)a, try taking out a factor of (1-a)a-1
     
  4. Oct 22, 2008 #3
    Thanks
     
  5. Oct 22, 2008 #4

    Mark44

    Staff: Mentor

    You really should get into the habit of including "=" between expessions that have the same value. If you don't, it will come back to bite you.
     
  6. Oct 23, 2008 #5
    a-a(1-a)a + a1-a(1-a)a-1

    = a-a(1-a)a + a1a-a(1-a)a (1-a)-1

    = a-a(1-a)a( 1 + a(1-a)-1)

    Like this?
     
  7. Oct 23, 2008 #6

    Mark44

    Staff: Mentor

    Yep, that's it.
     
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