Question

Answer 1

\(\Leftrightarrow x^2-2\sqrt{5x}+5=0\\ \Leftrightarrow\left(x-\sqrt{5}\right)^2=0\\ \Leftrightarrow x-\sqrt{5}=0\\ \Leftrightarrow x=\sqrt{5}\)

Answer 2

\(x^2-2\sqrt{5}x+5=0\\ \Leftrightarrow x^2-2.\sqrt{5}.x+\sqrt{5^2}=0\\ \Leftrightarrow\left(x-\sqrt{5}\right)^2=0\\ \Leftrightarrow x-\sqrt{5}=0\\ \Leftrightarrow x=\sqrt{5}\)