Решите уравнение 4x^2-20=0.

\[4x² - 20 = 0\]

\[4 \cdot \left( x^{2} - 5 \right) = 0\]

\[x^{2} - 5 = 0\]

\[\left( x - \sqrt{5} \right)\left( x + \sqrt{5} \right) = 0\]

\[x - \sqrt{5} = 0\ \ \ \ \ \ \ \ \ \ x + \sqrt{5} = 0\]

\[x = \sqrt{5}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x = - \sqrt{5}\]

\[Ответ:x = \sqrt{5};\ x = - \sqrt{5}.\]