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$ E = 1-(\sqrt{45}-\sqrt{20}-\sqrt{3})(\sqrt{20}-\sqrt{45}-\sqrt{3})\\ \ \ \ = 1 - (3\sqrt{5}-2\sqrt{5}-\sqrt{3})(2\sqrt{5}-3\sqrt{5}-\sqrt{3})\\ \ \ \ = 1 - (\sqrt{5} - \sqrt{3})(-\sqrt{5}-\sqrt{3})\\ \ \ \ = 1 - (-\sqrt{3}+\sqrt{5})(-\sqrt{3}-\sqrt{5})\\ \ \ \ = 1 - [(-\sqrt{3})^2-5] \ \ \ = 1 - (3-5)\\ \ \ \ = 1 - (-2)\\ \ \ \ = 3 $ $#nc2394$