x³ - 3x² + 1 -3x=x³+1-3x²-3x=(x+1)(x²+x+1)-3x(x+1)

=(x+1)(x²+x+1-3x)

=(x+1)(x²-2x+1)

=(x+1)(x-1)²

xinh xắn đáng iu

woa xinh thế dễ thưn lắm Hoàng Thị Ngọc Anh

\(a^2+b^2+c^2=1\Rightarrow\left|a\right|;\left|b\right|;\left|c\right|\le1\)

\(\Rightarrow\left|a^3\right|\le a^2;\left|b^3\right|\le b^2;\left|c^3\right|\le c^2\)

\(\Rightarrow a^3+b^3+c^3\le\left|a^3\right|+\left|b^3\right|+\left|c^3\right|\le a^2+b^2+c^2=1\)

Dấu "=" xảy ra khi \(\left(a;b;c\right)=\left(1;0;0\right);\left(0;1;0\right);\left(0;0;1\right)\)

Vậy S = 0 + 0 + 1 = 1.