If $\frac{1}{|x|-3}≤\frac{1}{2}$, then value of $x$:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → $x ∈(-∞,-5] ∪ (-3,3) ∪ [5,∞)$ **
Solve the inequality:
$\displaystyle \frac{1}{|x|-3} \le \frac12$
1. Domain
$|x| - 3 \neq 0 \;\Rightarrow\; |x| \neq 3$ So $x \neq 3$ and $x \neq -3$.
2. Consider two cases based on the sign of the denominator
Case 1: $|x| - 3 < 0$ → $|x| < 3$
Then the denominator is negative.
$\displaystyle \frac{1}{\text{negative}}$ is always negative.
RHS is positive ($\frac12$).
A negative number is always $\le$ a positive number.
So all $x$ with $|x| < 3$ satisfy the inequality:
$(-3,\,3)$
Case 2: $|x| - 3 > 0$ → $|x| > 3$
Denominator positive → multiply without changing inequality:
$\displaystyle \frac{1}{|x|-3} \le \frac12$
Multiply both sides by $(|x|-3)$:
$1 \le \frac12(|x|-3)$
Multiply by 2:
$2 \le |x|-3$
Add 3:
$|x| \ge 5$
Thus:
$x \le -5$ or $x \ge 5$
Final Answer
${(-\infty,-5] \;\cup\; (-3,3) \;\cup\; [5,\infty)}$