Question

Tìm x,y,z biết: 2x=3y; 4y=5z và x+y-z= 11

Answer 1

\(2x=3y\Rightarrow\dfrac{x}{3}=\dfrac{y}{2}\Rightarrow\dfrac{x}{15}=\dfrac{y}{10}\)

\(4y=5z\Rightarrow\dfrac{y}{5}=\dfrac{z}{4}\Rightarrow\dfrac{y}{10}=\dfrac{z}{8}\)

\(\Rightarrow\dfrac{x}{15}=\dfrac{y}{10}=\dfrac{z}{8}=\dfrac{x+y-z}{15+10-8}=\dfrac{11}{17}\)

\(\Rightarrow\left\{{}\begin{matrix}x=\dfrac{15.11}{17}=\dfrac{165}{17}\\y=\dfrac{10.11}{17}=\dfrac{110}{17}\\z=\dfrac{8.11}{17}=\dfrac{88}{17}\end{matrix}\right.\)