Ta có: \(\dfrac{a}{3}=\dfrac{b}{4}\)
\(\dfrac{b}{2}=\dfrac{c}{5}\Rightarrow\dfrac{b}{4}=\dfrac{c}{10}\)
\(\Rightarrow\dfrac{a}{3}=\dfrac{b}{4}=\dfrac{c}{10}\)
Áp dụng tính chất dãy tỉ số bằng nhau:
\(\dfrac{a}{3}=\dfrac{b}{4}=\dfrac{c}{10}=\dfrac{a-c+b}{3-10+4}=\dfrac{3}{-3}=-1\)
\(\Rightarrow\left\{{}\begin{matrix}a=\left(-1\right).3=-3\\b=\left(-1\right).4=-4\\c=\left(-1\right).10=-10\end{matrix}\right.\)
\(\dfrac{a}{3}=\dfrac{b}{4};\dfrac{b}{2}=\dfrac{c}{5}\Rightarrow\dfrac{b}{4}=\dfrac{c}{10}\\ \Rightarrow\dfrac{a}{3}=\dfrac{b}{4}=\dfrac{c}{10}\)
Áp dụng t/c dãy tỉ số bằng nhau:
\(\dfrac{a}{3}=\dfrac{b}{4}=\dfrac{c}{10}=\dfrac{a+b-c}{3+4-10}=\dfrac{3}{-3}=-1\\ \Rightarrow\left\{{}\begin{matrix}a=-1\cdot3=-3\\b=-1\cdot4=-4\\c=-1\cdot10=-10\end{matrix}\right.\)
