CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2000

  • question_answer
    If\[3{{p}^{2}}=5p+2\]and\[3{{q}^{2}}=5q+2\]where\[n\ne q,\] then the equation whose roots are\[3p-2q\]and\[3q-2p\]is:

    A)  \[5{{x}^{2}}-3x-100=0\]

    B)         \[5{{x}^{2}}+3x+100=0\]

    C)         \[3{{x}^{2}}-5x+100=0\]

    D)         \[3{{x}^{2}}+5x-100=0\]

    E)         \[3{{x}^{2}}-5x-100=0\]

    Correct Answer: E

    Solution :

    Given that,  \[3{{p}^{2}}-5p-2=0\] \[\Rightarrow \]               \[(3p+1)(p-2)=0\] \[\Rightarrow \]               \[p=-\frac{1}{3},2\] and        \[3{{q}^{2}}-5q-2=0\] \[\Rightarrow \]               \[(3q+1)\,(q-2)=0\] \[\Rightarrow \]               \[q=\frac{-1}{3},\,2\] Since,    \[p\ne q\Rightarrow p=-\frac{1}{3},q=2\] Now,     \[(3p-2q)=-1-4=-5\] and        \[(3p-2p)=6+\frac{2}{3}=\frac{20}{3}\]   \[\therefore \]Equation is                 \[{{x}^{2}}-\left( -5+\frac{20}{3} \right)x+\frac{(-5)(20)}{3}=0\] \[\Rightarrow \]               \[3{{x}^{2}}-5x-100=0\]


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