BCECE Engineering BCECE Engineering Solved Paper-2008

  • question_answer
    If \[\sqrt{9{{x}^{2}}+6x+1}<(2-x),\]then

    A) \[x\in \left( -\frac{3}{2},\frac{1}{4} \right)\]

    B)         \[x\in \left( -\frac{3}{2},\frac{1}{4} \right]\]

    C)  \[x\in \left[ -\frac{3}{2},\frac{1}{4} \right)\]

    D)         \[x<\frac{1}{4}\]

    Correct Answer: A

    Solution :

    \[\sqrt{9{{x}^{2}}+6x+1}<(2-x)\] \[\Rightarrow \]\[\sqrt{{{(3x+1)}^{2}}}<(2-x)\] \[\Rightarrow \]\[\pm \,(3x+1)<2-x\] Taking positive sign                                 \[3x+1<2-x\]                 \[\Rightarrow \]               \[x<\frac{1}{4}\] Taking negative sign                                 \[-3x-1<2-x\]                 \[\Rightarrow \]               \[-2x<3\] \[\Rightarrow \]               \[x>-\frac{3}{2}\]                 \[\therefore \]  \[x\in \left( -\frac{3}{2},\frac{1}{4} \right)\]


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