[tex]\it 20+2\sqrt5\cdot[2\sqrt{300}+2\cdot(3\sqrt{45}-2\sqrt{75})] =\\ \\ =20+2\sqrt5 \cdot[2\sqrt{100\cdot3}+2\cdot(3\sqrt{9\cdot5}-2\sqrt{25\cdot3})] = \\ \\ =20+2\sqrt5 \cdot[20\sqrt{3}+18\sqrt5-20\sqrt{3})] = \\ \\ =20+40\sqrt{15} +180- 40\sqrt{15} = 200[/tex]
