340 (1,4)помогите срочно(

№340, 1)

$(\frac{\sqrt{5}}{\sqrt{5}-2}-\frac{5}{2+\sqrt{5}})(5+\sqrt{5})=(\frac{\sqrt{5}(\sqrt{5}+2)-5(\sqrt{5}-2)}{(\sqrt{5}-2)(\sqrt{5}+2)})(5+\sqrt{5})=\\(\frac{(\sqrt{5})^2+2\sqrt{5}-5\sqrt{5}+10}{(\sqrt{5})^2-2^2})(5+\sqrt{5})=(\frac{5-3\sqrt{5}+10}{5-4})(5+\sqrt{5})=\\(15-3\sqrt{5})(5+\sqrt{5})=3(5-\sqrt{5})(5+\sqrt{5})=3(5^2-(\sqrt{5})^2)=\\3(25-5)=3*20=60$

№340, 4)

$(\frac{\sqrt{13}}{\sqrt{13}-\sqrt{2}}+\frac{\sqrt{2}}{\sqrt{13}+\sqrt{2}})(\frac{2\sqrt{26}-11}{17})=\\(\frac{\sqrt{13}(\sqrt{13}+\sqrt{2})+\sqrt{2}(\sqrt{13}-\sqrt{2})}{(\sqrt{13}-\sqrt{2})(\sqrt{13}+\sqrt{2})})(\frac{2\sqrt{26}-11}{17})=\\(\frac{(\sqrt{13})^2+\sqrt{13*2}+\sqrt{2*13}-(\sqrt{2})^2}{(\sqrt{13})^2-(\sqrt{2})^2})(\frac{2\sqrt{26}-11}{17})=(\frac{13+2\sqrt{26}-2}{13-2})(\frac{2\sqrt{26}-11}{17})=\\(\frac{2\sqrt{26}+11}{11})(\frac{2\sqrt{26}-11}{17})=\\$ $\frac{(2\sqrt{26}+11)(2\sqrt{26}-11)}{11*17}=\frac{(2\sqrt{26})^2-11^2}{187}=\frac{104-121}{187}=\frac{-17}{187}=-\frac{1}{11}$