Tính giá trị các biểu thức sau

 $$\begin{gathered} \mathrm{a}) \sqrt{2-\sqrt{3}}.\sqrt{2+\sqrt{3}} \\ \mathrm{b}) \sqrt{3\sqrt{2-2\sqrt{3}}}.\sqrt{3\sqrt{2}+2\sqrt{3}} \\ \mathrm{c}) {(\sqrt{\sqrt{3}+\sqrt{2}}+\sqrt{\sqrt{3}+\sqrt{2}})}^2\mathrm{d}) (1+\sqrt{2}-\sqrt{3}).(1-\sqrt{2}+\sqrt{3}) \end{gathered}$$
Tính 
$\mathrm{Giúp} \mathrm{mk} \mathrm{với} \mathrm{nhé}.\mathrm{Mk} \mathrm{xin} \mathrm{cảm} \mathrm{ơn} \mathrm{ạ}.\mathrm{Mk} \mathrm{sẽ} \mathrm{tick} \mathrm{cho}$