Đáp án:
._.
Giải thích các bước giải:
`6/(11x)=9/(2y)=18/(5z)`
`=> (11x)/6=(2y)/9=(5z)/18`
`=>` $\dfrac{x}{{\dfrac{6}{{11}}}}=\dfrac{y}{{\dfrac{9}{{2}}}}=\dfrac{z}{{\dfrac{18}{{5}}}}$
$=\dfrac{-x+y+z}{-{\dfrac{6}{{11}}}+{\dfrac{9}{{2}}}+{\dfrac{18}{{5}}}}$
$=\dfrac{-120}{\dfrac{831}{{110}}}=\dfrac{-4400}{277}$
`=>` $\begin{cases}x=\dfrac{-2400}{277}\\y=\dfrac{-19800}{277}\\z=\dfrac{-15840}{277}\end{cases}$
