Đặt \(\frac{x}{12}=\frac{y}{9}=\frac{z}{5}=k\Rightarrow x=12k;y=9k;z=5k\)
\(xyz=12k.9k.5k=540.k^3=20\Rightarrow k^3=\frac{1}{27}\Rightarrow k=\frac{1}{3}\)
\(\Rightarrow x=12.\frac{1}{3}4;y=9.\frac{1}{3}=3;z=5.\frac{1}{3}=\frac{5}{3}\)
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