\(x^2+y^2-2x+4y+5=0\)
=>\(x^2-2x+y^2+4y+5=0\)
=>\(x^2-2x1+1-1+y^2+2y2+2^2+1=0\)
=>\(\left(x-1\right)^2\left(y+2\right)^2=0\)
Vì\(\left\{{}\begin{matrix}\left(x-1\right)^2\ge0\\\left(y+2\right)^2\ge0\end{matrix}\right.\)\(\Rightarrow\left\{{}\begin{matrix}x-1=0\\y+2=0\end{matrix}\right.\)\(\Rightarrow\left\{{}\begin{matrix}x=1\\y=-2\end{matrix}\right.\)
