Ta có `:`

`a + b + c = 6`

`=> ( a+ b + c)^2 = 36`

`=> a^2 + b^2 + c^2 + 2 ( ab +bc+ca ) = 36`

Mà `a^2 + b^2 +c^2 = 12`

`=> 2 (ab+bc+ca) = 24`

`=> ab + bc + ca = 12`

`=> ab + bc + ca = a^2 + b^2 + c^2`

 `=> 2a^2 + 2b^2 + 2c^2 = 2ab + 2bc + 2ca`

`=> 2a^2 + 2b^2 + 2c^2 - 2ab - 2bc- 2ca = 0`

`=> ( a^2 - 2ab + b^2) + ( b^2 - 2bc + c^2 ) + ( c^2 - 2ca + a^2 ) = 0`

`=> ( a - b )^2 + (b-c)^2 +(c-a)^2 = 0`

`=> a-b = b-c = c-a = 0`

`=>a =b=c`

Mà `a + b +c = 6`

`=> a = b = c = 2`

Thay vào P : ( 2 - 3 )^2025 + (2-3)^2025 + (2-3)^2025`

`=> (-1)^2025 + (-1)^2025 + (-1)^2025`

`=> -1 + (-1) + (-1)`

`=> P = -3`