RAJASTHAN ­ PET Rajasthan PET Solved Paper-2004

  • question_answer
    The solutions of\[|{{x}^{2}}-x-6|=x+2\]are

    A)  \[-2,\text{ }2,\text{ }4\]           

    B)  \[-2,\text{ }2,-4\]

    C)  4, 3, 3            

    D)  \[3,\text{ }2,-2\]

    Correct Answer: A

    Solution :

     \[|{{x}^{2}}-x-6|=x+2\] or       \[{{x}^{2}}-x-6=\pm (x+2)\] On taking \['+'\]sign, \[{{x}^{2}}-x-6=x+2\] \[\Rightarrow \] \[{{x}^{2}}-2x-8=0\] \[\Rightarrow \] \[(x-4)(x+2)=0\] \[\Rightarrow \] \[x=4,-2\] On taking\['-'\]sign \[{{x}^{2}}-x-6=-(x+2)\] \[\Rightarrow \] \[{{x}^{2}}-4=0\] \[\Rightarrow \] \[(x-2)(x+2)=0\] \[\Rightarrow \] \[x=2,-2\] Hence, solutions of given equations are\[-2,2,4\].


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