\(\frac{x^2}{\sqrt{5}}-\sqrt{20}=0\)
\(\Leftrightarrow\frac{1}{\sqrt{5}}\left(x^2-10\right)=0\)
\(\Leftrightarrow x^2-10=0\)
\(\Leftrightarrow x^2=10\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=\sqrt{10}\\x=-\sqrt{10}\end{array}\right.\)
\(\frac{x^2}{\sqrt{5}}-\sqrt{20}=0\Leftrightarrow x^2=\sqrt{20}.\sqrt{5}\Leftrightarrow x^2=10\Leftrightarrow x=\pm\sqrt{10}\)
\(\frac{x^2}{\sqrt{5}}-\sqrt{20}=0\)
\(\Rightarrow\frac{1}{\sqrt{5}}\left(x^2-10\right)=0\)
\(\Rightarrow x^2=10\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=\sqrt{10}\\x=-\sqrt{10}\end{array}\right.\)
