JEE Main & Advanced Mathematics Equations and Inequalities Question Bank Self Evaluation Test - Linear Inequalities

  • question_answer
    If \[\frac{\left| x+3 \right|+x}{x+2}>1,\] then \[x\in \]

    A) \[(-5,-2)\]

    B) \[(-1,\infty )\]

    C) \[(-5,-2)\cup (-1,\infty )\]

    D) None of these

    Correct Answer: C

    Solution :

    [c] We have \[\frac{\left| x+3 \right|+x}{x+2}>1\]
    \[\Rightarrow \frac{\left| x+3 \right|+x}{x+2}-1>0\Rightarrow \frac{\left| x+3 \right|-2}{x+2}>0\]
    Now, two cases arise:
    Case I: When \[x+3\ge 0,i.e.x\ge -3\] then,
    \[\frac{\left| x+3 \right|-2}{x+2}>0\Rightarrow \frac{x+3-2}{x+2}>0\]
    \[\Rightarrow \frac{x+1}{x+2}>0\]
    \[\Rightarrow \{(x+1)>0\,\,and\,\,x+2>0\}\]
    or \[\{x+1<0\,\,and\,\,x+2<0\}\]
    \[\Rightarrow \{x>-1\,\,and\,\,x>-2\}\] or \[\{x<-1\,\,and\,\,x<-2\}\]
    \[\Rightarrow x>-1\,\,or\,\,x<-2\]
    \[\Rightarrow x\in (-1,\infty )\,\,or\,\,x\in (-\infty ,-2)\]
    \[\Rightarrow x\in (-3,-2)\cup (-1,\infty )\][Since \[x\ge -3\]]    ? (i)
    Case II: When \[x+3<0,i.e.x<-3\]
    \[\frac{\left| x+3 \right|-2}{x+2}>0\Rightarrow \frac{-x-3-2}{x+2}>0\]
    \[\Rightarrow \frac{-(x+5)}{x+2}>0\Rightarrow \frac{x+5}{x+2}<0\]
    \[\Rightarrow (x+5<0\,\,and\,\,x+2>0)\,\,\,or\,\,\,(x+5>0)\]
    and \[x+2<0)\]
    \[\Rightarrow (x<-5andx>-2)\]
    Or \[(x>-5andx<-2)\] it is not possible.
    \[\Rightarrow x\in (-5,-2)\]                         (ii)
    Combining (i) and (ii), the required solution is
    \[x\in (-5,-2)\cup (-1,\infty )\]


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