Question

2x = 3y ; 4y = 5z và \(2x+3y-4z=56\)

Answer 1

GIÚP MÍNH VỚI MN ƠIIIIIIII!

Answer 2

\(2x=3y\Rightarrow\dfrac{x}{3}=\dfrac{y}{2}\Rightarrow\dfrac{x}{15}=\dfrac{y}{10};4y=5z\Rightarrow\dfrac{y}{5}=\dfrac{z}{4}\Rightarrow\dfrac{y}{10}=\dfrac{z}{8}\\ \Rightarrow\dfrac{x}{15}=\dfrac{y}{10}=\dfrac{z}{8}\)

Áp dụng t/c dtsbn:

\(\dfrac{x}{15}=\dfrac{y}{10}=\dfrac{z}{8}=\dfrac{2x}{30}=\dfrac{3y}{30}=\dfrac{4z}{32}=\dfrac{2x+3y-4z}{30+30-32}=\dfrac{56}{28}=2\\ \Rightarrow\left\{{}\begin{matrix}x=30\\y=20\\z=16\end{matrix}\right.\)