$\text{2x = 3y = 5z và x + y - z = 95}$
$\text{Có: BCNN(2; 3; 5) = 30}$
$\text{nên $\dfrac{2x}{30}$ = $\dfrac{3y}{30}$ = $\dfrac{5z}{30}$}$
$\text{⇔ $\dfrac{x}{15}$ = $\dfrac{y}{10}$ = $\dfrac{z}{6}$}$
$\text{Áp dụng tính chất dãy tỉ số bằng nhau ta có:}$
$\text{$\dfrac{x}{15}$ = $\dfrac{y}{10}$ = $\dfrac{z}{6}$ = $\dfrac{x + y - z}{15 + 10 - 6}$ = $\dfrac{95}{19}$ = 5}$
$\text{Do đó:}$
$\text{$\dfrac{x}{15}$ = 5 ⇒ x = 75}$
$\text{$\dfrac{y}{10}$ = 5 ⇒ y = 50}$
$\text{$\dfrac{z}{6}$ = 5 ⇒ z = 30}$
$\text{Vậy x = 75}$
$\text{y = 50}$
$\text{z = 30}$
