Question

mong mọi người giúp mình

 

Answer 1

Câu 4:

\(x:y:z=2:3:4\Rightarrow\dfrac{x}{2}=\dfrac{y}{3}=\dfrac{z}{4}=k\Rightarrow x=2k,y=3k,z=4k\)

\(P=\dfrac{x+2y-z}{x-2y-z}=\dfrac{2k+6k-4k}{2k-6k-4k}=\dfrac{4k}{-8k}=-\dfrac{4}{2}=-2\)