Question

Tìm các số x,y,z biết:\(\dfrac{x}{2}=\dfrac{y}{4}=\dfrac{z}{6}\)và x-y+z=8

Answer 1

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

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

\(\Rightarrow\dfrac{x}{2}=2\Rightarrow x=2.2=4\)

\(\dfrac{y}{4}=2\Rightarrow y=2.4=8\)

\(\dfrac{z}{6}=2\Rightarrow z=2.6=12\)

Answer 2

Theo tính chất dãy tỉ số bằng nhau, ta có:

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

\(\Rightarrow\)x =4

y =8

z =12