10th Class Mathematics Polynomials Question Bank MCQs - Polynomials

  • question_answer
    Given that one of the zeroes of the cubic polynomial \[a{{x}^{3}}+b{{x}^{2}}+cx+d\] is zero, the product of the other two zeroes is: (NCERT EXEMPLAR)

    A) \[-\frac{c}{a}\]  

    B) \[\frac{c}{a}\]

    C) \[0\]

    D) \[-\frac{b}{a}\]

    Correct Answer: B

    Solution :

    [b] Let \[p(x)=a{{x}^{3}}+b{{x}^{2}}+cx+d\]
    Let \[\alpha ,\beta \] and \[\gamma \] be the zeroes of \[p(x),\] where \[\alpha =0.\].
    We know that sum of product of zeroes taken two at a time
                \[=\frac{c}{a}=\alpha \beta +\beta \gamma +\gamma \alpha \]
    \[\Rightarrow \,\,\,\,\,\,\,\,\,\,\,0\times \beta +\beta \gamma +\gamma \times 0=\frac{c}{a}\]
    \[\Rightarrow \,\,\,\,\,\,\,\,\,\,\,\beta \gamma =\frac{c}{a}\]
    Hence, product of other two zeroes \[=\frac{c}{a}\].


You need to login to perform this action.
You will be redirected in 3 sec spinner