CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2007

  • question_answer
    If one root of the equation\[{{x}^{2}}+px+12=0\]is 4, while the equation\[{{x}^{2}}+px+q=0\]has equal roots, then the value of q is

    A)  \[4\]                                    

    B)  \[12\]

    C)  \[3\]                    

    D)         \[\frac{29}{4}\]

    E)  \[\frac{49}{4}\]

    Correct Answer: E

    Solution :

    Let 4 and a be the roots of the equation \[{{x}^{2}}+px+12=0\]. \[\therefore \]  \[4a=12\Rightarrow \alpha =3\] And        \[4+3=-p\Rightarrow p=-7\] \[\therefore \]Equation\[{{x}^{2}}+px+q=0\]will reduce to \[{{x}^{2}}-7x+q=0\] Let this equation have P, P as its roots. \[\therefore \] \[2\beta =7\Rightarrow \beta =\frac{7}{2}\]and\[{{\beta }^{2}}=q\] \[\Rightarrow \]               \[q={{\left( \frac{7}{2} \right)}^{2}}=\frac{49}{4}\]


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