\[\boxed{\mathbf{629\ (629).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[x^{2} - 2x = 0\]
\[x(x - 2) = 0\]
\[x = 0,\ \ x = 2\]
\[Ответ:x = 2;0.\]
\[x^{2} - 7 = 0\]
\[x^{2} = 7\]
\[x = \sqrt{7},\ \ x = - \sqrt{7}\ \]
\[Ответ:\ x = - \sqrt{7};\sqrt{7}.\]