Помогите пж с решением 1. 2√7x√21 2. (2√2-√50)*√2 3. (4√80-√125): √5

[latex]2 \sqrt{7}* \sqrt{21}=2 \sqrt{7*7*3}=2*7\sqrt{3} =14\sqrt{3} \\ \\ (2 \sqrt{2}-\sqrt{50} )*\sqrt{2}=(2 \sqrt{2}-\sqrt{25*2} )*\sqrt{2}=(2 \sqrt{2}-5\sqrt{2} )*\sqrt{2}= \\ =(-3 \sqrt{2})*\sqrt{2}=-3*2=-6 \\ \\ \frac{4 \sqrt{80} - \sqrt{125}}{ \sqrt{5}} =\frac{4 \sqrt{16*5} - \sqrt{25*5}}{ \sqrt{5}} =\frac{4*4 \sqrt{5} -5 \sqrt{5}}{ \sqrt{5}} =\frac{16\sqrt{5} -5 \sqrt{5}}{ \sqrt{5}} =\frac{11\sqrt{5}}{ \sqrt{5}} =11[/latex]