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

\(-2\sqrt{300}=-2⋅\sqrt{100}⋅\sqrt{3}=-2⋅10⋅\sqrt{3}=-20\sqrt{3}\text{.}\)

\(\sqrt{\frac{9}{16}}={\sqrt{9} \over \sqrt{16}}=\frac{3}{4}\text{.}\)

\({35\sqrt{200} \over 5\sqrt{10}}={35 \over 5}⋅{\sqrt{200} \over \sqrt{10}}=7\sqrt{20}=7⋅\sqrt{4}⋅\sqrt{5}=7⋅2⋅\sqrt{5}=14\sqrt{5}\)