Solve: x−2x+1>0\frac{x - 2}{x + 1} > 0x+1x−2>0
x<−1x < -1x<−1 or x>2x > 2x>2
−1<x<2-1 < x < 2−1<x<2
x∈(−∞,−1)∪(2,∞)x \in (-\infty, -1) \cup (2, \infty)x∈(−∞,−1)∪(2,∞)
x=−1x = -1x=−1 is a boundary