Question

giúp mik vs ạ, mik dg vội 

Answer 1

a) \(\dfrac{x}{2}=\dfrac{y}{3}=\dfrac{z}{4}=\dfrac{2y}{6}=\dfrac{3z}{12}=\dfrac{x+2y-3z}{2+6-12}=\dfrac{-20}{-4}=5\)

\(\Rightarrow\left\{{}\begin{matrix}x=5.2=10\\y=5.3=15\\z=5.4=20\end{matrix}\right.\)

b) \(7x=3y\Rightarrow\dfrac{x}{3}=\dfrac{y}{7}\)

Áp dụng t/c dtsbn:

\(\dfrac{x}{3}=\dfrac{y}{7}=\dfrac{x-y}{3-7}=\dfrac{16}{-4}=-4\)

\(\Rightarrow\left\{{}\begin{matrix}x=\left(-4\right).3=-12\\y=\left(-4\right).7=-28\end{matrix}\right.\)