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ngtuan96

$$a^3+b^3=(a+b)(a^2-ab+b^2)=-1$$
$$\Longleftrightarrow (a+b)[(a+b)^2-3ab]=-1$$
$$\Longleftrightarrow 1-3ab=1$$
$$\Longleftrightarrow ab=0$$
$\Longrightarrow (a;b)=(0;-1)$ hoặc $(a;b)=(-1;0)$$\Longrightarrow (a-b)^{2004}=1$
 
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