Question

\(\dfrac{x}{7}\)=\(\dfrac{y}{3}\)và y-x=2

Answer 1

\(\dfrac{x}{7}=\dfrac{y}{3}.\\ \Rightarrow3x=7y.\\ \Rightarrow x=\dfrac{7}{3}y.\\ y-x=2.\\ \Rightarrow y-\dfrac{7}{3}y=2.\\ \Leftrightarrow-\dfrac{4}{3}y=2.\\ \Leftrightarrow y=\dfrac{-3}{2}.\\ \Rightarrow x=\dfrac{-7}{2}.\)

Answer 2

`x/y=y/3`

Ta có :

`(y-x)/(3-7)=2/-4=1/-2`

`=>x/7=1/-2<=>x=-7/2`

`=>y/3=-1/2<=>y=-3/2`