Question

giúp mình với đang cần gấp

Answer 1

\(\dfrac{x}{2}=\dfrac{y}{5}=k\)

\(\Rightarrow\left\{{}\begin{matrix}x=2k\\y=5k\end{matrix}\right.\)

\(\Rightarrow xy=10k^2=90\Rightarrow k=\pm3\)

\(\Rightarrow\left\{{}\begin{matrix}x=\pm6\\y=\pm15\end{matrix}\right.\)

Vậy \(\left(x;y\right)\in\left\{\left(6;15\right),\left(-6;-15\right)\right\}\)