10th Class Mathematics Quadratic Equations Question Bank Quadratic Equation

  • question_answer
    Find the roots of the equation \[{{l}^{2}}\left( {{m}^{2}}-{{n}^{2}} \right){{x}^{2}}+{{m}^{2}}\left( {{n}^{2}}-{{l}^{2}} \right)x+{{n}^{2}}\left( {{l}^{2}}-{{m}^{2}} \right)=0\]

    A)  \[\frac{{{n}^{2}}\left( {{l}^{2}}-{{m}^{2}} \right)}{{{l}^{2}}\left( {{m}^{2}}-{{n}^{2}} \right)},l\]

    B)  \[\frac{-{{m}^{2}}\left( {{l}^{2}}-{{m}^{2}}+{{n}^{2}} \right)}{{{l}^{2}}\left( {{m}^{2}}-{{n}^{2}} \right)},\frac{1}{2}\]

    C)  \[\frac{{{n}^{2}}\left( {{l}^{2}}+{{m}^{2}}+{{n}^{2}} \right)}{{{m}^{2}}\left( {{m}^{2}}-{{n}^{2}} \right)},1\]

    D)  \[\frac{-{{m}^{2}}\left( {{l}^{2}}+{{n}^{2}} \right)}{mn\left( {{m}^{2}}-{{n}^{2}} \right)},\frac{1}{2}\]

    Correct Answer: A

    Solution :

    (a): In the equation \[a{{x}^{2}}+bx+c=0\] when \[a+b+c=0\], then the roots are 1 and \[\frac{c}{a}\]. Use the following justification and compare: here,\[a={{l}^{2}}\left( {{m}^{2}}-{{n}^{2}} \right);b={{m}^{2}}\left( {{n}^{2}}-{{l}^{2}} \right)\]and \[c={{n}^{2}}\left( {{l}^{2}}-{{m}^{2}} \right)\]      


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