Với `x > 0` có:
`[\sqrt{x}-1]/\sqrt{x}+[2\sqrt{x}+1]/[x+\sqrt{x}]`
`=[(\sqrt{x}-1)(\sqrt{x}+1)+2\sqrt{x}+1]/[\sqrt{x}(\sqrt{x}+1)]`
`=[x-1+2\sqrt{x}+1]/[\sqrt{x}(\sqrt{x}+1)]`
`=[\sqrt{x}(\sqrt{x}+2)]/[\sqrt{x}(\sqrt{x}+1)]`
`=[\sqrt{x}+2]/[\sqrt{x}+1]`