Đáp án:
$\text{(b-c)³ +(c-a)³ +(a-b)³}$
$\text{(=a³-3a²b+3ab²-b³+b³-3b²c+3bc²-c³+c³-3ac²+3a²c-a³}$
$\text{(=(a³-a³)+(b³-b³)+(c³-c³)-3(a²b+ac²-ab²+b²c-a²c)}$
$\text{(=3[(a²b-ab²)+(ac²-bc²)-(a²c-b²c)]}$
$\text{(=3[ab(a-b)+c²(a-b)-c(a²-b²)]}$
$\text{(=3(a-b)[ab+c²-c(a+b)]}$
$\text{(=3(a-b)(ab+c²-ac-bc)}$
$\text{(=3(a-b)[(ab-ac)-(bc-c²)]}$
$\text{(=3(a-b)[a(b-c)-c(b-c)]}$
$\text{(=3(a-b)(a-c)(b-c)}$