Detailed process: ①(a-b)? =a？ +b？ -2ab(b-a) after switching? =b？ +a？ -2ab

② BA+AC+CB after ②a b+ BC+CA AB exchange \

AC+c b+ ba-BC is the same as the original formula after interchange.

After communication, cb+ba+ac/

③a？ b+b？ c+c？ A if you only switch ab, b? a+a？ c+c？ B is different from the original formula, and it will be the same as the original formula only under special circumstances (when ab is the same).

So ① ② is ③ not.