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Homework Help: Adding exponents

  1. Nov 10, 2004 #1
    Well it appears that as i get higher in math, i lose the stuff i learned awhile ago. This type has me stumped for some reason.


    x^3 + X^5=0 Or another one X^3 + x^4=0

    I can break them down to X^3(1+X^2)=0 or X^3(X +1)=0

    I just can seem to solve these simple guys.
     
  2. jcsd
  3. Nov 10, 2004 #2

    dav2008

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    Gold Member

    I'm not sure where you're having problems.

    x3+x5=0
    x3(1 + x2)=0
    x3=0 or 1 + x2=0
    x=0 (Assuming you only want real solutions)
     
  4. Nov 10, 2004 #3
    Hmm found something but cant explain the rule (help explaining please)

    Got it to X^3(1+X)=0

    for some reason you break it down to 2 solutions
    x^3=0 and 1+x=0

    since the first one doesnt work, the second one is the answer, which i can solve. X=-1
     
  5. Nov 10, 2004 #4

    dav2008

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    The first one solves for x=0
     
  6. Nov 10, 2004 #5

    Zurtex

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    If a*b=0 then it is obvious that either a=0, b=0 or a and b=0. So you need to look at both a being 0 or b being 0. This is why in general in maths we like things to equal 0 so we can solve them. For example a*b=1 doesn't tell us anything about a or b.
     
  7. Nov 10, 2004 #6
    Thanks guys, due to a brain fart this problem took me like 30min cuz i didnt factor, then i couldnt remember the zero thing till about 10min ago. I thought im gona be a garbage man after this simple brain freeze. Last brain freeze was adding two digit number:)
     
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