2. Questions Bank
  3. 9th Class
  4. Mathematics
  5. Polynomials

9th Class Mathematics Polynomials Question Bank Polynomials

  • question_answer
    If\[\frac{x}{y}+\frac{y}{x}=-1(x,\,\,y\ne 0)\], what is the value of\[{{x}^{3}}-{{y}^{3}}\]?

    A)  \[1\]                            

    B)  \[-1\]               

    C)  \[\frac{1}{2}\]             

    D)         \[0\]    

    Correct Answer: D

    Solution :

    Given \[\frac{x}{y}+\frac{y}{x}=-1\Rightarrow \frac{{{x}^{2}}+{{y}^{2}}}{xy}=-1\] \[\Rightarrow \]\[{{x}^{2}}+{{y}^{2}}+xy=0\]                       ?..(i) \[{{x}^{3}}-{{y}^{3}}=(x+y)({{x}^{2}}+xy+{{y}^{2}})=0\]


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