Ta có: \(\left|x-2020\right|\ge0\forall x\)
\(\left|y-2021\right|\ge0\forall y\)
Do đó: \(\left|x-2020\right|+\left|y-2021\right|\ge0\forall x,y\)
mà \(\left|x-2020\right|+\left|y-2021\right|=0\)
nên \(\left\{{}\begin{matrix}x-2020=0\\y-2021=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=2020\\y=2021\end{matrix}\right.\)
Vậy: (x,y)=(2020;2021)