Внесите множитель под знак корня: -4*корень из 3.

\[- 4\sqrt{3} = - \sqrt{16 \cdot 3} = - \sqrt{48}\]

\[\sqrt{16 + b^{2} - 8b} = \sqrt{(b - 4)^{2}} = |b - 4|\]

\[b = 5,1 \Longrightarrow |5,1 - 4| = 1,1.\]

\[\ \frac{2 + \sqrt{2}}{\sqrt{3} + \sqrt{6}} = \frac{\sqrt{2}\left( \sqrt{2} + 1 \right)}{\sqrt{3}\left( 1 + \sqrt{2} \right)} = \frac{\sqrt{2}}{\sqrt{3}} = \sqrt{\frac{2}{3}}\]