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Factoring Limits

  1. Dec 11, 2011 #1
    Okay so I've been teaching myself (with the aid of the mighty internet & several friends) algebra & now calculus. I have found that I didn't do too good at high school for various reasons. Some good...some not good. Anyway...

    I have a (what is probably a basic question) about factoring limit questions. I understand that with an equation like below (which results in 0, you need to factor it)

    Lim x^2 -5x - 6
    x->2 ------------
    x^2 - 4

    factored it works out to (x-3)(x-2).

    I can manage that. What is the approach taken when you have something like

    Lim x^2 + 3x -24
    x->4 ------------
    x^2 + 8

    I don't know what to do in a situation like this, I don't know how to break it into a (x a)(x b) situation. I hope this thread isn't looked at & thought 'what a twit' I should say that I am aware of the quadratic equation............
  2. jcsd
  3. Dec 11, 2011 #2
    In this problem you can actually just substitute [itex]x = 4 [/itex] since the result is defined (no 0 in the denominator or an infinity anywhere) :)
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