Tính

1.$\frac{2}{3+2\sqrt{2}}-\frac{2}{3-\sqrt{8}}$
2,$\sqrt{\frac{3\sqrt{5}-1}{2\sqrt{5}+3}}-\sqrt{\frac{\sqrt{5}+11}{7-2\sqrt{5}}}$
3,$$\begin{gathered} giai phuong trinh \\ \sqrt{x^2-4x+4}=x+2 \end{gathered}$$
4. $$\begin{gathered} cho bieu thuc \\ M=\frac{\sqrt{x}+2}{\sqrt{x}-3}-\frac{\sqrt{x}+1}{\sqrt{x}-2}-3\times \frac{\sqrt{x}-1}{x-5\sqrt{x}+6} \\ voi x\ge 0;x khac 4;9 \\ a,thu gon bieu thuc M \\ b,tim gia tri cua x de M <-1 \end{gathered}$$