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    Q.Find the range of values of k for which the equation x^2-kx+(k+3)=0 has real roots.

    So this means that b^2-4ac >= 0

    But the answer in the book and solution book are both same which doesn't make sense. Can someone please solve this here so I can match my answer? Im pretty sure it's wrong in the book.
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    (Original post by Hamzah249)
    Q.Find the range of values of k for which the equation x^2-kx+(k+3)=0 has real roots.

    So this means that b^2-4ac >= 0

    But the answer in the book and solution book are both same which doesn't make sense. Can someone please solve this here so I can match my answer? Im pretty sure it's wrong in the book.
    Surely if two books agree on the answer then there isn't a problem?! :confused:

    What does your book say the answer should be?
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    (Original post by davros)
    Surely if two books agree on the answer then there isn't a problem?! :confused:

    What does your book say the answer should be?
    Book says the answer is -2<K<6

    When my answer is K<=-2, K>=6

    Thats why I want someone to solve it and see that the answer in the* book is totally wrong or maybe im missing something
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    k^2-4a(k+3)>0

    Go from there.
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    (Original post by Vikingninja)
    k^2-4a(k+3)>0

    Go from there.
    I did, thats how I got the final answer that a is 1 and I wrote >= looks like the book considered this as no real roots and took the equation as k^2-4(1)(k+3)<0
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    (Original post by Vikingninja)
    k^2-4a(k+3)>0

    Go from there.
    I know it's not allowed in the rules to solve question here and just give hints but I have solved it and I need to compare with someone else can you solve it here?
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    (Original post by Hamzah249)
    I did, thats how I got the final answer that a is 1 and I wrote >= looks like the book considered this as no real roots and took the equation as k^2-4(1)(k+3)<0
    Could you post a picture of the question from the book please. Because I'm getting that -2 and 6 as k = 0 but the range between doesn't make sense.
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    (Original post by Vikingninja)
    Could you post a picture of the question from the book please. Because I'm getting that -2 and 6 as k = 0 but the range between doesn't make sense.
    https://gyazo.com/a5511ee5de7b49764c9675ac6ff37e0c
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    Ok yeah I'm getting the same answer as you on this question.
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    (Original post by Vikingninja)
    Ok yeah I'm getting the same answer as you on this question.
    Then it looks like the 2 books including step by step solution book are wrong on this one.
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    (Original post by serah.exe)
    Here you go, excuse the paint skills lmao.
    Attachment 461681
    Oh well that makes sense.
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    (Original post by serah.exe)
    Here you go, excuse the paint skills lmao.
    Attachment 461681
    That doesn't make any sense plot a graph and you will see that its k<-2 and K>6
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    (Original post by Vikingninja)
    Oh well that makes sense.
    Please explain?
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    (Original post by Hamzah249)
    That doesn't make any sense plot a graph and you will see that its k<-2 and K>6
    Yep, those workings do not make sense. Should be what you said.
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    (Original post by serah.exe)
    Here you go, excuse the paint skills lmao.
    Attachment 461681
    Shouldn't your b=-k?
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    (Original post by Illiberal Liberal)
    Shouldn't your b=-k?
    It's squared.
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    Excuse my skills but aren't you suppose to be taking the part outside of the U shape graph https://gyazo.com/aa0690b2a656699353ee75f7007abcaa
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    Another dank quick graph example.

    But the answer -2<K<6 should only appear if the graph was like this https://gyazo.com/aa14cd420634cfea8c55ef7272bb8020
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    k<-2
    k>6

    (My apologies to serah.exe )
    Spoiler:
    Show

    I haven't done maths in a while :getmecoat:
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    I just found the minimum point and it actually only works if it is equal to or smaller than -2 or greater than 6 so yeah im wtfing now. Should ask your teacher when you next see them.
 
 
 
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