Giải thích các bước giải:
a.Ta có :
$2x=3y=5z=k\to x=\dfrac k2, y=\dfrac k3, z=\dfrac k5$
$\to x+y-z=\dfrac{k}{2}+\dfrac{k}{3}-\dfrac{k}{5}=\dfrac{19k}{30}=95\to k=150$
$\to x=75, y=50, z=30$
b.Ta có :
$15x=10y=6z=k\to x=\dfrac{k}{15}, y=\dfrac{k}{10}, z=\dfrac{k}{6}$
$\to x+y+z=\dfrac{k}{15}+\dfrac{k}{10}+\dfrac{k}{6}=\dfrac k3=20\to k=60$
$\to x=4, y=6, z=10$