Ta có: \(\sqrt{x}+\sqrt{y}=\sqrt{1998}=3\sqrt{222}\)
Từ đây ta có:
\(\left\{{}\begin{matrix}\sqrt{x}=a\sqrt{222}\\\sqrt{y}=b\sqrt{222}\end{matrix}\right.\left(a,b>0\right)\)
\(\Rightarrow a+b=3\)
\(\Rightarrow\left(a,b\right)=\left(1,2;2,1\right)\)
\(\Rightarrow\left(x,y\right)=...\)