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Math Help - find set of values, district roots

  1. #1
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    find set of values, district roots

    hi,

    i nned to know how to answer this question:

    Find a set of values of x for the equation have two district roots, x^2-6x+k=0

    im not too sure how i would complete this question, so could someone provide some help please?

    thanks!
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  2. #2
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    Re: find set of values, district roots

    Quote Originally Posted by andyboy179 View Post
    hi,

    i nned to know how to answer this question:

    Find a set of values of x for the equation have two district roots, x^2-6x+k=0

    im not too sure how i would complete this question, so could someone provide some help please?

    thanks!
    If it has two distinct roots then the discriminant must be greater than 0: b^2 - 4ac > 0

    Where a=1, b=-6, c=k
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  3. #3
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    Re: find set of values, district roots

    -6^2-4x1x4>0
    -36+-16>0
    -52>0?
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    Re: find set of values, district roots

    Quote Originally Posted by andyboy179 View Post
    -6^2-4x1x4>0
    -36+-16>0
    -52>0?
    a = 1 , b = -6 , c = k

    order of operations? try again ...

    (-6)^2 - 4(1)(k) > 0
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  5. #5
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    Re: find set of values, district roots

    oh poo!

    -6^2-4x1xk>0
    -36+-4k>0
    >36+4k
    36/4= 9
    K=9?
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  6. #6
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    Re: find set of values, district roots

    Quote Originally Posted by andyboy179 View Post
    oh poo!

    -6^2-4x1xk>0
    -36+-4k>0
    >36+4k 36/4= 9
    K=9?
    no ...

    1. apparently, you do not understand the difference between (-6)^2 and -6^2.

    2. +4k ?

    3. you are solving an inequality ... where did the equal sign come from?
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  7. #7
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    Re: find set of values, district roots

    -6^2-4x1xk>0
    36+-4k>0
    36>4k
    36/4= 9
    k>9?
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  8. #8
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    Re: find set of values, district roots

    Quote Originally Posted by andyboy179 View Post
    -6^2-4x1xk>0
    36+-4k>0
    36>4k
    36/4= 9
    k>9?
    You changed the direction of the inequality in the last line but there is no need to since you were dividing by +4.

    k < 9
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  9. #9
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    Re: find set of values, district roots

    so what would be the set of values for x?
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  10. #10
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    Re: find set of values, district roots

    Quote Originally Posted by andyboy179 View Post
    so what would be the set of values for x?
    That's a good question, are you sure the question doesn't ask for the values of k instead of x?

    When we work out the nature of the roots (whether they're real/distinct) it's the coefficients of x that matter rather than values of x itself
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  11. #11
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    Re: find set of values, district roots

    it is definetly x! umm im not too sure how to do the next part then.
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