Question

Answer 1

x = 5

y = 3

Answer 2

\(3x=5y\Rightarrow\dfrac{x}{5}=\dfrac{y}{3}\Rightarrow\dfrac{x^2}{25}=\dfrac{y^2}{9}\)

Áp dụng t/c dtsbn:

\(\dfrac{x^2}{25}=\dfrac{y^2}{9}=\dfrac{x^2-y^2}{25-9}=\dfrac{16}{16}=1\)

\(\Rightarrow\left\{{}\begin{matrix}x^2=25\\y^2=9\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x=5\\y=3\end{matrix}\right.\\\left\{{}\begin{matrix}x=-5\\y=-3\end{matrix}\right.\end{matrix}\right.\)