\(\sqrt{28} = \sqrt{4} ⋅ \sqrt{7} = 2 \sqrt{7} \text{.}\)

\(-2 \sqrt{50} = -2 ⋅ \sqrt{25} ⋅ \sqrt{2} = -2 ⋅ 5 ⋅ \sqrt{2} = -10 \sqrt{2} \text{.}\)

\(\sqrt{\frac{49}{100}} = {\sqrt{49} \over \sqrt{100}} = \frac{7}{10} \text{.}\)

\({32 \sqrt{72} \over 8 \sqrt{3}} = {32 \over 8} ⋅ {\sqrt{72} \over \sqrt{3}} = 4 \sqrt{24} = 4 ⋅ \sqrt{4} ⋅ \sqrt{6} = 4 ⋅ 2 ⋅ \sqrt{6} = 8 \sqrt{6}\)

\(\sqrt{3\frac{17}{25}} = \sqrt{\frac{92}{25}} = {\sqrt{92} \over \sqrt{25}} = {\sqrt{92} \over 5} = \frac{1}{5} \sqrt{92} = \frac{1}{5} ⋅ 2 ⋅ \sqrt{23} = \frac{2}{5} \sqrt{23} \text{.}\)