\(a,\frac{2\sqrt{2}}{\sqrt{3}+1}=\frac{2\sqrt{2}\left(\sqrt{3}-1\right)}{\left(\sqrt{3}-1\right)\left(\sqrt{3}+1\right)}=\frac{2\sqrt{2}\left(\sqrt{3}-1\right)}{3-1}=\frac{2\sqrt{2}\left(\sqrt{3}-1\right)}{2}=\sqrt{6}-\sqrt{2}\)
\(b,\frac{\sqrt{2}+1}{\sqrt{2}-1}=\frac{\left(\sqrt{2}+1\right)\left(\sqrt{2}+1\right)}{\left(\sqrt{2}-1\right)\left(\sqrt{2}+1\right)}=3+2\sqrt{2}\)