4. Find the value of k so that the quadratic equation 9x^2- 3kx = has equal roots ​

Question

4. Find the value of k so that the quadratic
equation 9x^2- 3kx = has equal roots

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Melody 3 weeks 2021-08-21T22:20:20+00:00 1 Answer 0 views 0

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    2021-08-21T22:21:39+00:00

    Answer:

    Step-by-step expk = 4


    Step-by-step explanation:



    Our given equation is :



    9 x² – 3 k x + k = 0



    Comparing with a x² + b x + c = 0 we get :


    a = 9


    b = – 3  k


    c = k .



    Whenever we are told that the equation has equal roots then :


    b² = 4 a c


    This method can be used effectively to calculate the value of k .



    ( – 3 k )² = 4 ( 9 ) ( k )


    ⇒ 9 k² = 36 k


    ⇒ k² = 36 k / 9


    ⇒ k² = 4 k


    ⇒ k = 4



    The value of k is 4 .

    NOTE :

    If the equation had real and unequal roots , then :


    b² > 4 ac



    If the equation had imaginary roots then :


    b² < 4 aclanation:

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