(−2,2)(-2,2)(−2,2)
(−1,1)(-1,1)(−1,1)
(−2,2)∪(−1,2)(-2,2) \cup(-1,2)(−2,2)∪(−1,2)
(−∞,−1)∪(3,∞)(-\infty,-1) \cup(3, \infty)(−∞,−1)∪(3,∞)
(−∞,∞)(-\infty, \infty)(−∞,∞)