$\frac{x}{-4}=$ $\frac{y}{-7}=$ $\frac{z}{3}=$ $\frac{-2.x+y+5z}{(-2).(-4)+(-7)+5.3}=$ $\frac{-2.x+y+5z}{16}$
$\frac{x}{-4}=$ $\frac{y}{-7}=$ $\frac{z}{3}=$ $\frac{2.x-3.y+-6.z}{2.(-4)-3.(-7)-6.3}=$ $\frac{2.x-3.y-6.z}{-5}$
→$\frac{-2.x+y+5z}{16}=$ $\frac{2.x-3.y-6.z}{-5}$
→$\frac{-2.x+y+5z}{2.x-3.y-6.z}=$ $\frac{16}{-5}$