a) Dễ thấy [tex]x^3\vdots 2\Rightarrow x\vdots 2\Rightarrow x=2m\Rightarrow 8m^3+2y^3+4z^3=9!\Rightarrow 2y^3\vdots 4\Rightarrow y^3\vdots 2\Rightarrow y\vdots 2\Rightarrow y=2n\Rightarrow 8m^3+16n^3+4z^3=9!\Rightarrow 2m^3+4n^3+z^3=\frac{9!}{4}\in \mathbb{N}\Rightarrow z^3\vdots 4(do\frac{9!}{4}\vdots 4)\Rightarrow z\vdots 2\Rightarrow z=2p\Rightarrow 2m^3+4n^3+8p^3=1.2.3.5.6.7.8.9\Rightarrow m^3+2n^3+4p^3=1.3.5.6.7.8.9\Rightarrow m^3\vdots 2\Rightarrow m\vdots 2\Rightarrow m=2a\Rightarrow 8a^3+2n^3+4p^3=1.3.5.6.7.8.9\Rightarrow 2n^3\vdots 4\Rightarrow n^3\vdots 2\Rightarrow n\vdots 2\Rightarrow n=2b\Rightarrow 8a^3+16b^3+4p^3=1.3.5.6.7.8.9\Rightarrow 2a^3+4b^3+p^3=1.3^2.5.7.4.9\Rightarrow p^3\vdots 2\Rightarrow p\vdots 2\Rightarrow p=2c\Rightarrow \left\{\begin{matrix} x=4a\vdots 4\\ y=4b\vdots 4\\ z=4c\vdots 4 \end{matrix}\right.[/tex]
[TẶNG BẠN] TRỌN BỘ Bí kíp học tốt 08 môn
