Given the set a = {a | x = a + X / X & # 178; - 2}, and the set B = {x | x + A / X & # 178; - 2 = 1}, then can the set B be a single element set? If the set a can be represented by enumeration, if not, please explain the reason Set a {- 9 / 4 ± √ 2} I can only answer: - 9 / 4 ± √ 2? I'm really powerless

Given the set a = {a | x = a + X / X & # 178; - 2}, and the set B = {x | x + A / X & # 178; - 2 = 1}, then can the set B be a single element set? If the set a can be represented by enumeration, if not, please explain the reason Set a {- 9 / 4 ± √ 2} I can only answer: - 9 / 4 ± √ 2? I'm really powerless

① When B is an empty set, x = ± √ 2
a=x^3-3x=±√2
② When B is a nonempty set
⊿ = 1 + 4 (a + 2) = 0, the solution is a = - 9 / 4