Решебник по алгебре 8 класс Мерзляк Задание 890

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\[1)\ \sqrt{x} = 2\]

\[x = 4\]

\[Ответ:x = 4.\ \ \ \ \]

\[2)\ \sqrt{x} = \frac{1}{4}\]

\[x = \frac{1}{16}\]

\[Ответ:x = \frac{1}{16}.\]

\[3)\ \sqrt{x} - 3 = 0\]

\[\sqrt{x} = 3\]

\[x = 9\]

\[Ответ:x = 9.\]

\[4)\ 2\sqrt{x} - 7 = 0\]

\[\sqrt{x} = \frac{7}{2}\]

\[x = \frac{49}{4}\]

\[x = 12,25\]

\[Ответ:x = 12,25.\]

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

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

\[Ответ:корней\ нет.\]

\[6)\frac{1}{4}\sqrt{x} + 5 = 0\]

\[\frac{1}{4}\sqrt{x} = - 5\]

\[\sqrt{x} = - 20\]

\[Ответ:корней\ нет.\]

\[7)\sqrt{7x} - 4 = 0\]

\[\sqrt{7x} = 4\]

\[7x = 16\]

\[x = \frac{16}{7}\]

\[Ответ:x = \frac{16}{7}.\]

\[8)\ \sqrt{7x - 4} = 0\]

\[7x - 4 = 0\]

\[x = \frac{4}{7}\ \]

\[Ответ:x = \frac{4}{7}.\]

\[9)\ \sqrt{7x - 4} = 2\]

\[7x - 4 = 4\]

\[7x = 8\]

\[x = \frac{8}{7}\]

\[Ответ:x = \frac{8}{7}.\]

\[10)\ \frac{28}{\sqrt{x}} = 7\]

\[\sqrt{x} = 4\]

\[x = 16\]

\[Ответ:x = 16.\]

\[11)\ \frac{15}{\sqrt{x + 4}} = 3\]

\[\sqrt{x + 4} = 5\]

\[x + 4 = 25\]

\[x = 21\]

\[Ответ:x = 21.\]

\[12)\ \sqrt{4 + \sqrt{3 + x}} = 5\]

\[4 + \sqrt{3 + x} = 25\]

\[\sqrt{3 + x} = 21\]

\[3 + x = 441\]

\[x = 438\]

\[Ответ:x = 438.\]