Решите пжж скорей даю 40 балов!!!!

Решите задачу:

$1)\ \ (\sqrt5+\sqrt3-\sqrt{15})(\sqrt5-\sqrt3)+\sqrt{75}=\\\\=(\sqrt5+\sqrt3)(\sqrt5-\sqrt3)-\sqrt{15}(\sqrt5-\sqrt3)+\sqrt{75}=\\\\=(5-3)-\sqrt{75}+\sqrt{45}+\sqrt{75}=2+\sqrt{9\cdot 5}=2+3\sqrt5$

$2)\ \ \dfrac{\sqrt5-\sqrt3}{\sqrt5+\sqrt3}+\dfrac{\sqrt5+\sqrt3}{\sqrt5-\sqrt3}=\dfrac{(\sqrt5-\sqrt3)^2+(\sqrt5+\sqrt3)^2}{(\sqrt5-\sqrt3)\cdot (\sqrt5+\sqrt3)}=\\\\\\=\dfrac{2\cdot5+2\cdot 3}{5-3}=\dfrac{16}{2}=8$

$3)\ \ 0,3\sqrt{10}\cdot 0,2\sqrt{15}\cdot 0,5\sqrt6=0,03\sqrt{10\cdot 15\cdot 6}=0,03\sqrt{900}=\\\\=0,03\cdot 30=0,9$