Find the range of xxx such that 1x2−4≤1\frac{1}{x^2 - 4} \leq 1x2−41≤1.
x \in (-\infty, -2) \cup (2, \infty)
x \in (-\sqrt{5}, -2) \cup (2, \sqrt{5})
x \in [-\sqrt{5}, \sqrt{5}]
x \in (-\infty, -\sqrt{5}] \cup (-2, 2) \cup [\sqrt{5}, \infty)