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Math Help - Homework Help?

  1. #1
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    Homework Help?

    Okay, so I don't understand what I'm doing wrong, so I need some help.
    lim x->3 x^2+x-6 / x^2-9
    I'm supposed to find the limit, which I can't figure out

    Also:
    lim x->4- √x -2 / x-4
    which is, again, finding the limit.
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  2. #2
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    Quote Originally Posted by Gengar View Post
    Okay, so I don't understand what I'm doing wrong, so I need some help.
    lim x->3 x^2+x-6 / x^2-9
    I'm supposed to find the limit, which I can't figure out

    straight substitution of x = 3 gets you 6/0 ... what does that tell you about the limit?

    Also:
    lim x->4- √x -2 / x-4
    which is, again, finding the limit.

    hint ...

    (√x -2)/(x-4) = (√x -2)/[(√x -2)(√x +2)]
    ...
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  3. #3
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    Correct about the straight substitution but the thing is, the answer for that one is supposed to be 5/6 :/
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  4. #4
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    Quote Originally Posted by Gengar View Post
    Correct about the straight substitution but the thing is, the answer for that one is supposed to be 5/6 :/
    not for the limit you posted

    lim x->3 x^2+x-6 / x^2-9
    ... check it.

    if x \to -3 , then the limit is \frac{5}{6}
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  5. #5
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    I didn't even see the negative in front of the three in the book lol
    Thank you
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