\(\left(x-1\right)^2+\left(3-y\right)^2\text{≤}\) (1)
Vì \(\left\{{}\begin{matrix}\left(x-1\right)^2\text{≥}0\\\left(3-y\right)^2\text{≥}0\end{matrix}\right.\)
⇒\(\left(x-1\right)^2+\left(3-y\right)^2\text{≥}0\) (2)
Từ (1) và (2):
⇒\(\left(x-1\right)^2+\left(3-y\right)^2=0\)
⇒\(\left\{{}\begin{matrix}\left(x-1\right)^2=0\\\left(3-y\right)^2=0\end{matrix}\right.\) ⇒\(\left\{{}\begin{matrix}x=1\\y=3\end{matrix}\right.\)