Đáp án + giải thích các bước giải:
`a+b+c=0`
`->a+b=-c`
`->(a+b)^3=-c^3`
`->a^3+b^3+c^3=-3ab(a+b)=-3ab(-c)=3abc`
`->(a^3+b^3+c^3)/3=(3abc)/3=abc`
`a+b+c=0`
`->a+b=-c`
`->(a+b)^2=c^2`
`->a^2+b^2+2ab=c^2`
`->a^2+b^2+c^2=2c^2-2ab`
`->(a^2+b^2+c^2)=c^2-2ab`
`a+b+c=0`
`->a+b=-c`
`->(a+b)^5=-c^5`
`->a^5+b^5+5ab(a^3+b^3)+10a^2b^2(a+b)=-c^5`
`->a^5+b^5+c^5=-5ab(a^3+b^3+2a^2b+2ab^2)`
`->a^5+b^5+c^5=-5ab[(a+b)^3-3ab(a+b)+2ab(a+b)]`
`->a^5+b^5+c^5=-5ab[-c^3-ab(a+b)]`
`->a^5+b^5+c^5=-5ab[-c^3-ab(-c)]`
`->a^5+b^5+c^5=5abc(c^2-ab)`
`->(a^5+b^5+c^5)/5=abc(c^2-2ab)=(a^3+b^3+c^3)/3 .(a^2+b^2+c^2)/2`
