Сократите дробь: (16-x)/(4+корень из x).

\[\ \frac{16 - x}{4 + \sqrt{x}} = \frac{(4 - \sqrt{x})(4 + \sqrt{x})}{4 + \sqrt{x}} = 4 - \sqrt{x}\]

\[\frac{4}{2\sqrt{3} + 1} - \frac{4}{2\sqrt{3} - 1} =\]

\[= \frac{4 \cdot \left( 2\sqrt{3} - 1 \right) - 4 \cdot \left( 2\sqrt{3} + 1 \right)}{\left( 2\sqrt{3} \right)^{2} - 1^{2}} =\]

\[= \frac{8\sqrt{3} - 4 - 8\sqrt{3} - 4}{12 - 1} = \frac{- 8}{11}\]

\[\ 3 \cdot \sqrt{1\frac{9}{16}} - 1 = 3 \cdot \sqrt{\frac{25}{16}} - 1 =\]

\[= 3 \cdot \frac{5}{4} - 1 = \frac{15}{4} - 1 = \frac{11}{4} = 2\frac{3}{4}\ \]