\(\left\{{}\begin{matrix}\dfrac{a}{2}=\dfrac{b}{3}\\\dfrac{b}{5}=\dfrac{c}{4}\end{matrix}\right.\)\(\Rightarrow\dfrac{a}{10}=\dfrac{b}{15}=\dfrac{c}{12}\)
Áp dụng t/c dtsbn:
\(\dfrac{a}{10}=\dfrac{b}{15}=\dfrac{c}{12}=\dfrac{a-b+c}{10-15+12}=\dfrac{-28}{7}=-4\)
\(\Rightarrow\left\{{}\begin{matrix}a=\left(-4\right).10=-40\\b=\left(-4\right).15=-60\\c=\left(-4\right).12=-48\end{matrix}\right.\)