\[\boxed{\text{373\ (373).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ x^{2} = 9\]
\[x = \pm 3\]
\[Ответ:x = 3;\ x = - 3.\]
\[2)\ x^{2} = \frac{36}{49}\]
\[x = \pm \frac{6}{7}\]
\[Ответ:x = \frac{6}{7};x = \ - \frac{6}{7}.\]