The function FX = x / (x-a) x is not equal to a, if a = - 2, it is proved that f (x) increases monotonically in (negative infinity, - 2)
F (x) = x / (x + 2) let x1, X2 belong to (negative infinity, - 2), and x1
F (x) = x / (x + 2) let x1, X2 belong to (negative infinity, - 2), and x1