\[\boxed{\text{126\ (126).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[1)\ \sqrt{4x + 20}\]
\[4x + 20 \geq 0\]
\[4x \geq - 20\]
\[x \geq - 5\]
\[Ответ:при\ x \in \lbrack - 5;\ + \infty).\]
\[2)\ \sqrt{5 - 14x}\]
\[5 - 14x \geq 0\]
\[5 \geq 14x\]
\[x \leq \frac{5}{14}\]
\[Ответ:при\ x \in \left( - \infty;\frac{5}{14} \right\rbrack.\]
\[3)\ \frac{10}{\sqrt{4x + 10}}\]
\[4x + 10 > 0\]
\[4x > - 10\]
\[x > - \frac{5}{2}\]
\[Ответ:при\ x \in ( - 2,5;\ + \infty).\]