A=$\frac{1}{1+\sqrt{5}}+\frac{1}{\sqrt{5}+\sqrt{9}}+\frac{1}{\sqrt{9}+\sqrt{13}}+...+\frac{1}{\sqrt{2021})+\sqrt{2025}}$ 

=$\frac{1-\sqrt{5}}{1-5}+\frac{\sqrt{5}-\sqrt{9}}{5-9}+\frac{\sqrt{9}+\sqrt{13}}{9-13}+...+\frac{\sqrt{2021}+\sqrt{2025}}{2021-2025}$ 

= $\frac{1-\sqrt{5}}{-4}+\frac{\sqrt{5}-\sqrt{9}}{-4}+\frac{\sqrt{9}-\sqrt{13}}{-4}+...+\frac{\sqrt{2021}-\sqrt{2025}}{-4}$ 

= $\frac{1-\sqrt{5}+\sqrt{5}-\sqrt{9}+\sqrt{9}-\sqrt{13}+...+\sqrt{2021}-\sqrt{2025}}{-4}$ 

= -$\frac{1}{4}$ 

=-0.25

B=($\frac{1}{3-\sqrt{5}}$-$\frac{1}{3+\sqrt{5}}$).$\frac{5-\sqrt{5}}{\sqrt{5}-1}$

=$\frac{3+\sqrt{5}-(3-\sqrt{5})}{(3-\sqrt{5})(3+\sqrt{5})}$.$\frac{5-\sqrt{5}}{\sqrt{5}-1}$ 

=$\frac{3+\sqrt{5}-3+\sqrt{5}}{(3-\sqrt{5})(3+\sqrt{5})}$.$\frac{5-\sqrt{5}}{\sqrt{5}-1}$ 

=$\frac{2.\sqrt{5}}{(3-\sqrt{5})(3+\sqrt{5})}$.$\frac{5-\sqrt{5}}{\sqrt{5}-1}$ 

=$\frac{2.\sqrt{5}}{(3-\sqrt{5})(3+\sqrt{5})}$.$\frac{\sqrt{5}(\sqrt{5}-1)}{\sqrt{5}-1}$ 

=$\frac{2.\sqrt{5}}{(3-\sqrt{5})(3+\sqrt{5})}$.$\sqrt{5}$ 

=$\frac{2.5}{9-15}$

=$\frac{10}{-6}$

=-$\frac{5}{3}$

C=($\frac{1}{\sqrt{x}-1}$+$\frac{1}{x-\sqrt{x}}$):($\frac{1}{\sqrt{x}+1}$-$\frac{2}{1-x}$)

=($\frac{1}{\sqrt{x}-1}$+$\frac{1}{\sqrt{x}(\sqrt{x}-1)}$):($\frac{1}{\sqrt{x}+1}$+$\frac{2}{x-1}$)

=($\frac{\sqrt{x}+1}{\sqrt{x}(\sqrt{x}-1)}$):($\frac{1}{\sqrt{x}+1}$+$\frac{2}{(\sqrt{x}-1)(\sqrt{x}+1)}$)

=$\frac{\sqrt{x}+1}{\sqrt{x}(\sqrt{x}-1)}$:$\frac{\sqrt{x}-1+2}{(\sqrt{x}-1)(\sqrt{x}+1)}$

=$\frac{\sqrt{x}+1}{\sqrt{x}(\sqrt{x}-1)}$.$\frac{(\sqrt{x}-1)(\sqrt{x}+1)}{\sqrt{x}+1}$

=$\frac{\sqrt{x}+1}{\sqrt{x}(\sqrt{x}-1)}$.$(\sqrt{x}-1)$

=$\frac{\sqrt{x}+1}{\sqrt{x}}$

D=$(\sqrt{32}-\sqrt{18}+2\sqrt{2})$.$\sqrt{2}$-$\sqrt{25}$

=$(4.\sqrt{2}-3.\sqrt{2}+2\sqrt{2})$.$\sqrt{2}$-5

=$3.\sqrt{2}$.$\sqrt{2}$-5

=3.2-5

=6-5

=1