\[\boxed{\text{371\ (371).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[\textbf{а)}\ \sqrt{81 \cdot 900} = \sqrt{81} \cdot \sqrt{900} =\]
\[= 9 \cdot 30 = 270\]
\[\textbf{б)}\ \sqrt{0,36 \cdot 49} = \sqrt{0,36} \cdot \sqrt{49} =\]
\[= 0,6 \cdot 7 = 4,2\]
\[\textbf{в)}\ \sqrt{12\frac{1}{4}} = \sqrt{\frac{49}{4}} = \frac{\sqrt{49}}{\sqrt{4}} = \frac{7}{2} =\]
\[= 3,5\]
\[\textbf{г)}\ \sqrt{10\frac{9}{16}} = \sqrt{\frac{169}{16}} = \frac{\sqrt{169}}{\sqrt{16}} =\]
\[= \frac{13}{4} = 3\frac{1}{4} = 3,25\]
\[\boxed{\text{371.}\text{\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]
Пояснение.
Решение.
\[\textbf{а)}\ \sqrt{15} = \sqrt{3} \cdot \sqrt{5}\]
\[\textbf{б)}\ \sqrt{21} = \sqrt{3} \cdot \sqrt{7}\]
\[\textbf{в)}\ \sqrt{7a} = \sqrt{7} \cdot \sqrt{a}\]
\[\textbf{г)}\ \sqrt{3c} = \sqrt{3} \cdot \sqrt{c}\]