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Quick algebra questions.

  1. Feb 4, 2004 #1
    Hi, this is a bit of topic but I could not find any good algebra forums. Havn't done this since freshman yr so Im a bit rusty.

    1) 6x - x^2 = x

    *I set this to zero and factor and get -2, and 3. But it doesn't work when i plug it back in? where did I mess up?

    2) 5 - 35/x^2 = 0

    *No idea how to do it?

    3) Factor : 2x^4 - 32
    2(x+2)(x-2)(x+2)(x-2)

    4) Factor : 5y^3 + 2y^2 - 10y - 4
    (5y^3 + 2y^2)(-10y - 4)
    y^2(5y + 2) -2(5y + 2)
    (y^2 - 2)(5y + 2)

    * I think i can factor it more i don't know how.

    any help is appreciated
     
    Last edited: Feb 4, 2004
  2. jcsd
  3. Feb 4, 2004 #2

    ShawnD

    User Avatar
    Science Advisor

    -x^2 + 5x = 0
    x(-x + 5) = 0

    x = 0
    x = 5

    My calculator confirmed these answers.



    -35/x^2 = -5
    -35/-5 = x^2
    x^2 = 7
    x = sqrt(7)
    x = -sqrt(7)

    My calculator confirmed these answers.

    Your answer doesn't work. If you multiply those terms together you do not get what you started with.

    2(x^4 - 16)
    2(x^2 + 4)(x^2 - 4)
    2(x^2 + 4)(x + 2)(x - 2)

    I don't remember too much about grouping but it looks pretty good.
     
  4. Feb 4, 2004 #3
    U use calulators for these pros

    U can write [tex] y^2-2=y^2-\sqrt(2)^2[/tex]
     
  5. Feb 6, 2004 #4
    Re: Re: Quick algebra questions.

    It is done correctly the answer is just extraneous.
     
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