Ta có:\(4x=3y\Rightarrow\frac{x}{3}=\frac{y}{4},5y=3z\Rightarrow\frac{y}{3}=\frac{z}{5}\)
\(\Rightarrow\frac{x}{9}=\frac{y}{12},\frac{y}{12}=\frac{z}{15}\)
\(\Rightarrow\frac{x}{9}=\frac{y}{12}=\frac{z}{15}\)
\(\Rightarrow\frac{x}{9}=\frac{y}{12}=\frac{z}{15}=\frac{2x-3y+z}{2\cdot9-12\cdot3+15}=\frac{6}{-3}=-2\)(T/C..)
\(\Rightarrow x=-18,y=-24,z=-30\)