2. Questions Bank
  3. 10th Class
  4. Mathematics
  5. Related to Competitive Exam

10th Class Mathematics Related to Competitive Exam Question Bank Algebra

  • question_answer
    If one factor of the expression \[{{x}^{3}}+7k{{x}^{2}}-4kx+12\]is \[(x+3)\], then the value of k is

    A)  5                                            

    B)  \[\frac{1}{5}\]  

    C)  \[-\frac{13}{17}\]           

    D)         \[-\frac{17}{13}\]

    Correct Answer: B

    Solution :

     Since \[x+3=x-(-3)\] is a factor of                 \[f(x)={{x}^{3}}+7k{{x}^{2}}-4kx+12\] \[\therefore \]  \[f(-3)=0\] or            \[{{(-3)}^{3}}+7k{{(-3)}^{2}}-4k(-3)+12=0\] or            \[-27+63k+12k+12=0\] or            \[75k-15=0\] or            \[k=\frac{1}{5}\]


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