Question

Answer 1

Tham khảo:https://hoidapvietjack.com/q/604319/tim-xy-n-biet-36-y28x-20202

Answer 2

Từ đề bài ta được \(y^2\) chẵn và \(36-y^2=8\left(x-2020\right)^2\ge0\)

\(\Leftrightarrow-36\le y^2\le36\)

Do đó \(y^2=4\Leftrightarrow y=2\left(y\in N\right)\)

\(y=2\Leftrightarrow32=8\left(x-2020\right)^2\\ \Leftrightarrow\left(x-2020\right)^2=4\Leftrightarrow\left[{}\begin{matrix}x-2020=2\\2020-x=2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2022\\x=2018\end{matrix}\right.\)

Do đó \(\left(x;y\right)=\left\{\left(2022;2\right);\left(2018;2\right)\right\}\)