Упростите выражение (2- корень из 3)^2

\[\ \left( 2 - \sqrt{3} \right)^{2} = 4 - 4\sqrt{3} + 3 = 7 - 4\sqrt{3}\]

\[\frac{1}{2}\sqrt{12} < \frac{1}{3}\sqrt{45}\]

\[\frac{1}{4} \cdot 12 < \frac{1}{9} \cdot 45\]

\[3 < 5.\]

\[\ \frac{\sqrt{3} - 3}{\sqrt{5} - \sqrt{15}} = \frac{\sqrt{3}\left( 1 - \sqrt{3} \right)}{\sqrt{5}\left( 1 - \sqrt{3} \right)} = \frac{\sqrt{3}}{\sqrt{5}} = \sqrt{0,6}\]