SSC Sample Paper SSC-CGL TIER - I Sample Test Paper-10

  • question_answer
    The equation whose roots are twice the roots of the equation \[{{x}^{2}}-2x+4=0\]is:

    A) \[{{x}^{2}}-2x+4=0\]

    B) \[{{x}^{2}}-2x+16=0\]

    C) \[{{x}^{2}}-4x+8=0\]

    D) \[{{x}^{2}}-4x+16=0\]

    Correct Answer: D

    Solution :

    Let \[\alpha ,\beta \]be roots of \[{{x}^{2}}\]- 2x + 4 = 0 Then, \[\alpha +\beta =-\left( -2 \right)=2\Rightarrow \alpha \beta =4\] Quadratic equation whose roots are\[2\alpha ,\,\,2\beta \]is \[{{x}^{2}}-\left( 2\alpha +2\beta  \right)x+2\alpha \times 2\beta =0\] \[\Rightarrow \,{{x}^{2}}-2\left( \alpha +\beta  \right)x+4\alpha \beta =0\] \[\]


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