Задача 8. Решите уравнение    \(\sqrt {\frac{3}{{20 — 5x}}}  = 0,2.\)

Ответ

ОТВЕТ: — 11.

Решение

\(\sqrt {\frac{3}{{20 — 5x}}}  = \frac{1}{5}\,\,\,\,\, \Leftrightarrow \,\,\,\,\,\,\frac{3}{{20 — 5x}} = \frac{1}{{25}}\,\,\,\,\,\, \Leftrightarrow \,\,\,\,\,\left\{ {\begin{array}{*{20}{c}}{20 — 5x \ne 0\,\,}\\{20 — 5x = 75}\end{array}} \right.\,\,\,\,\,\, \Leftrightarrow \,\,\,\,\,\left\{ {\begin{array}{*{20}{c}}{x \ne 4\,\,\,\,\,\,}\\{x =  — 11}\end{array}} \right.\,\,\,\,\,\,\, \Leftrightarrow \,\,\,\,\,x =  — 11.\)

Ответ:  – 11.