https://olm.vn/hoi-dap/question/1076928.html
bạn tham khảo nhé
Đặt a : 6 = x => a = 6x
b : 6 = y => b = 6y
c : 6 = z => c = 6z
Ta có : a3 + b3 + c3 = (a . a . a) + (b . b . b) + (c . c . c)
= ( 6x . 6x . 6x ) + ( 6y . 6y . 6y ) + ( 6z . 6z . 6z )
= 6 ( x . x . x ) + 6 ( y . y . y ) + 6 ( z . z . z ) chia hết cho 6