Giải thích các bước giải:
g) Vì $\dfrac{x}{y} = \dfrac{7}{10} \to \dfrac{x}{7} = \dfrac{y}{10} \to \dfrac{x}{35} = \dfrac{y}{50}$
$\dfrac{y}{z} = \dfrac{5}{8} \to \dfrac{y}{5} = \dfrac{z}{8} \to \dfrac{y}{50} = \dfrac{z}{80}$
$\to \dfrac{x}{35} = \dfrac{y}{50} = \dfrac{z}{80} = k $
$\to x= 35k; y=50k; z=80k$
$ưto 2x-y+3z=2.35k-50k+3.80k = 104$
$\to 260k =104$
$\to k = \dfrac{2}{5}$
$\to x= 35.\dfrac{2}{5} = 14; y = \dfrac{2}{5}.50 = 20; z=\dfrac{2}{5} .80 = 32$
Vậy $(x,y,z) = (4,20,32)$
