Tính: c, $\frac{2}{\sqrt{2}}$ - $\frac{1}{\sqrt{3} - \sqrt{2}}$ + $\frac{2}{\sqrt{3} - 1}$

`2/(\sqrt3) - 1/(\sqrt3-\sqrt2)+2/(\sqrt3-1)`

`=(2\sqrt3)/3-(\sqrt3+\sqrt2)/(3-2)+(2(\sqrt3+1))/(3-1)`

`=(2\sqrt3)/3-\sqrt3-\sqrt2+\sqrt3+1`

`=(2\sqrt3)/3-(\sqrt2-1)`

`=(2\sqrt3)/3-(3(\sqrt2-1))/3`

`=(2\sqrt3 - 3\sqrt2+3)/3`