\(\dfrac{x}{2}=\dfrac{y}{3}\Leftrightarrow\dfrac{x}{8}=\dfrac{y}{12};\dfrac{y}{4}=\dfrac{z}{5}\Leftrightarrow\dfrac{y}{12}=\dfrac{z}{15}\\ \Leftrightarrow\dfrac{x}{8}=\dfrac{y}{12}=\dfrac{z}{15}\)
Áp dụng t/c dtsbn:
\(\dfrac{x}{8}=\dfrac{y}{12}=\dfrac{z}{15}=\dfrac{x+y-z}{8+12-15}=\dfrac{10}{5}=2\\ \Leftrightarrow\left\{{}\begin{matrix}x=16\\y=24\\z=30\end{matrix}\right.\)