\[\boxed{\text{348\ (348).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[\textbf{а)}\ x^{2} = 30\]
\[x = \pm \sqrt{30}\]
\[x \approx \pm 5,48.\]
\[\textbf{б)}\ 7x^{2} = 10\]
\[x^{2} = \frac{10}{7}\]
\[x = \pm \sqrt{\frac{10}{7}}\]
\[x \approx \pm 1,20.\]
\[\textbf{в)}\ (x - 3)^{2} = 12\]
\[x - 3 = \pm \sqrt{12}\]
\[x - 3 = \sqrt{12}\ \ \ \ \ \ \ \ \ \ \ x - 3 = - \sqrt{12}\]
\[x = \sqrt{12} + 3\ \ \ \ \ \ \ \ \ \ x = - \sqrt{12} + 3\]
\[x \approx 6,46\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x \approx - 0,46.\]
\[\textbf{г)}\ (x + 1)^{2} = 8\]
\[x + 1 = \pm \sqrt{8}\]
\[x + 1 = \sqrt{8}\ \ \ \ \ \ \ \ \ x + 1 = - \sqrt{8}\]
\[x = \sqrt{8} - 1\ \ \ \ \ \ \ \ x = - \sqrt{8} - 1\]
\[x \approx 1,83\ \ \ \ \ \ \ \ \ \ \ \ \ \ x \approx - 3,83.\]