`a)5\sqrt{3}+\sqrt{27}-\sqrt{75}+2\sqrt{48}`
`=5\sqrt{3}+3\sqrt{3}-5\sqrt{3}+8\sqrt{3}`
`=11\sqrt{3}`
`b)\frac{4}{5\sqrt{2}}-\frac{\sqrt{2}-\sqrt{10}}{1-\sqrt{5}}-\frac{\sqrt{2}}{1-\sqrt{2}}`
`=\frac{2\sqrt{2}}{5}-\frac{\sqrt{2}(1-\sqrt{5})}{1-\sqrt{5}}-\frac{\sqrt{2}(1+\sqrt{2})}{1-2}`
`=\frac{2\sqrt{2}}{5}-\sqrt{2}+\sqrt{2}(1+\sqrt{2})`
`=\frac{2\sqrt{2}}{5}-(\sqrt{2}-\sqrt{2}-2)`
`=\frac{2\sqrt{2}}{5}+2`
`=\frac{2\sqrt{2}+10}{5}`
