Cho a; b; c > 0. Tìm min: P = a^6/(b + c) + b^6/(c + a) + c^6/(a + b). Cho x; y; z > 0. Tìm max M = xyz/(x + y)(y + z)(z + x)

1. Cho a; b; c > 0. Tìm min:
P = a^6/(b + c) + b^6/(c + a) + c^6/(a + b)
2. Cho x; y; z > 0. Tìm max M = xyz/(x + y)(y + z)(z + x)