10th Class Mathematics Polynomials Question Bank MCQs - Polynomials

  • question_answer
    If one zero of the polynomial \[3{{x}^{2}}+8x+k\] is the reciprocal of the other, then value of k is:    (CBSE 2020)

    A) \[3\]

    B) \[-3\]

    C) \[\frac{1}{3}\]

    D) \[-\frac{1}{3}\]

    Correct Answer: A

    Solution :

    [a] Let \[f(x)=3{{x}^{2}}+8x+k\]
    According to question, \[\alpha \] and \[\frac{1}{\alpha }\]are the zeroes of the given polynomial \[f(x)\].
    \[\therefore \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\alpha \cdot \frac{1}{\alpha }=\frac{k}{3}\,\,\,\Rightarrow \frac{k}{3}=1\]
    \[\Rightarrow \,\,\,\,\,\,\,\,\,\,\,\,\,k=3\]


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