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Math Help - Limits problem , i cant solve

  1. #1
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    Limits problem , i cant solve

    Hey everyone again,

    I am having trouble with certain limit problems on my exam revision maths booklet , I have attached the questions and answers.

    I assume the steps involved to solve questions 6(b), 8(b), 10(a) are as followed: These questions

    step 1: Sub in the limits
    step 2: if it equals (0/0) we must factorise
    step 3: sub final values of factorise.

    I cant get the answer. I think it is basic operations I cant do but I am not entirely sure. Please correct me , where I am wrong.
    Attached Thumbnails Attached Thumbnails Limits problem , i cant solve-exam-revision-questions.jpg   Limits problem , i cant solve-exam-revision-questions-answers.jpg  
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  2. #2
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    Quote Originally Posted by student0451 View Post
    Hey everyone again,

    I am having trouble with certain limit problems on my exam revision maths booklet , I have attached the questions and answers.

    I assume the steps involved to solve questions 6(b), 8(b), 10(a) are as followed: These questions

    step 1: Sub in the limits
    step 2: if it equals (0/0) we must factorise
    step 3: sub final values of factorise.

    I cant get the answer. I think it is basic operations I cant do but I am not entirely sure. Please correct me , where I am wrong.
    I assume 6(b), 8(b) and 10(a) are the ones you want help with?

    Please type out each question and show what you've been able to do and say where you get stuck.
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  3. #3
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    hey fantastic,

    Here is what i have done,

    Question 6

    I have sub it in , i get (0/0) , I need to factorise but i cant find the factors.

    Question 7

    (-18/-18)

    I dont know exactly what to do after this step.



    question 10

    I simplify then factorize then sub it in
    Attached Thumbnails Attached Thumbnails Limits problem , i cant solve-question-6-7.jpg   Limits problem , i cant solve-question-10.jpg  
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  4. #4
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    Quote Originally Posted by student0451 View Post
    hey fantastic,

    Here is what i have done,

    Question 6

    I have sub it in , i get (0/0) , I need to factorise but i cant find the factors.

    Question 7

    (-18/-18)

    I dont know exactly what to do after this step.



    question 10

    I simplify then factorize then sub it in
    Please type out the questions, as requested earlier. I don't like having to click on things to see them properly and then having to switch back and forth between my reply and what I'm looking at.
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  5. #5
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    Quote Originally Posted by mr fantastic View Post
    Please type out the questions, as requested earlier. I don't like having to click on things to see them properly and then having to switch back and forth between my reply and what I'm looking at.
    The work you have shown is wrong. eg. When x = -3, x^2 does not equal -9. It equals (-3)^2 = 9. And 4^2 = 16 not 17.

    Note:

    \frac{2x^2 - 3x - 20}{x - 4} = \frac{(2x + 5)(x - 4)}{x - 4} = 2x + 5 provided x \neq 4.

    \frac{x^2 + 8x + 15}{x^2 - x - 12} = \frac{(x+3)(x + 5)}{(x + 3)(x - 4)} = \frac{x + 5}{x - 4} provided x \neq -3.

    And you urgently need to review how to factorise since you're obviously expected to be able to.
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  6. #6
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    I am sorry Fantastic, do I use the ladex editor? because I am relative new to this website.
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  7. #7
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    well thank you,

    I definitely need to learn this skill better.
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