`9)` Với `x >= 0,x \ne 9,x \ne 4` có:
`[\sqrt{x}+2]/[\sqrt{x}-3]-[\sqrt{x}+1]/[\sqrt{x}-2]-[3(\sqrt{x}-1)]/[x-5\sqrt{x}+6]`
`=[(\sqrt{x}+2)(\sqrt{x}-2)-(\sqrt{x}+1)(\sqrt{x}-3)-3\sqrt{x}+3]/[(\sqrt{x}-3)(\sqrt{x}-2)]`
`=[x-4-x+3\sqrt{x}-\sqrt{x}+3-3\sqrt{x}+3]/[(\sqrt{x}-3)(\sqrt{x}-2)]`
`=[-\sqrt{x}+2]/[(\sqrt{x}-3)(\sqrt{x}-2)]`
`=1/[3-\sqrt{x}]`
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`10)` Với `a > 0,a \ne 1` có:
`([\sqrt{a}+2]/[a+2\sqrt{a}+1]-[\sqrt{a}-2]/[a-1]).[a^2-2a+1]/[a-\sqrt{a}]`
`=[(\sqrt{a}+2)(\sqrt{a}-1)-(\sqrt{a}-2)(\sqrt{a}+1)]/[(\sqrt{a}+1)(a-1)].[(a-1)^2]/[\sqrt{a}(\sqrt{a}-1)]`
`=[a-\sqrt{a}+2\sqrt{a}-2-a-\sqrt{a}+2\sqrt{a}+2]/[\sqrt{a}+1].[a-1]/[\sqrt{a}(\sqrt{a}-1)]`
`=[2\sqrt{a}(a-1)]/[\sqrt{a}(a-1)]`
`=2`
