Từ \(\dfrac{x}{2}=\dfrac{y}{5}\Rightarrow\dfrac{x}{8}=\dfrac{y}{20}\)(1)
\(\dfrac{y}{4}=\dfrac{z}{6}\Rightarrow\dfrac{y}{20}=\dfrac{z}{30}\)(2)
Từ (1),(2) \(\Rightarrow\dfrac{x}{8}=\dfrac{y}{20}=\dfrac{z}{30}=\dfrac{x+y-z}{8+20-30}=\dfrac{26}{-2}=-13\)
(ADTCDTSBN và x+y-z=26)
\(\Rightarrow\left\{{}\begin{matrix}\dfrac{x}{8}=-13\\\dfrac{y}{20}=-13\\\dfrac{z}{30}=-13\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=-104\\y=-260\\z=-390\end{matrix}\right.\)
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