\(2x^2-4x+4xy+4y^2+4=0\)
\(\Rightarrow\left(x^2-4x+4\right)+\left(x^2+4xy+4y^2\right)=0\)
\(\Rightarrow\left(x^2-2.x.2+2^2\right)+\left(x^2+2.x.2y+\left(2y\right)^2\right)=0\)
\(\Rightarrow\left(x-2\right)^2+\left(x+2y\right)^2=0\)
\(\Rightarrow\hept{\begin{cases}x-2=0\\x+2y=0\end{cases}\Rightarrow}\hept{\begin{cases}x=2\\y=-1\end{cases}}\)
Chúc bạn học tốt.