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Math Help - Real Roots

  1. #1
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    Real Roots

    (i) Find the range of values of k for which the equation
    x^2-4x+k=5kx-4 has real roots

    (ii) Hence, deduce, giving a reason, the relationship about the curve
    y=(x-1)^2 and the line y=-5x-4


    I've solved part (i), the range is k>=0 or k<= -36/25

    I can't deduce the relationship for part (ii). Can anyone help??
    Thanks!!!!
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  2. #2
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by acc100jt View Post
    (i) Find the range of values of k for which the equation
    x^2-4x+k=5kx-4 has real roots

    (ii) Hence, deduce, giving a reason, the relationship about the curve
    y=(x-1)^2 and the line y=-5x-4


    I've solved part (i), the range is k>=0 or k<= -36/25

    I can't deduce the relationship for part (ii). Can anyone help??
    Thanks!!!!
    the first part should be k <=0 or k >= 36/25

    that is, (- \infty , 0] \cup [ 36/25, \infty)
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  3. #3
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by acc100jt View Post
    (i) Find the range of values of k for which the equation
    x^2-4x+k=5kx-4 has real roots

    (ii) Hence, deduce, giving a reason, the relationship about the curve
    y=(x-1)^2 and the line y=-5x-4
    Are you sure part i) isn't
    x^2 - 2x + k = 5kx - 4

    In that case you would be using k = 1...

    -Dan
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    thanks....topsquark
    I guess you are right. I did suspect that there is something wrong with the question
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