`P=(\frac{1}{x-\sqrt{x}}+\frac{\sqrt{x}}{x-1}):\frac{x\sqrt{x}-1}{x\sqrt{x}-\sqrt{x}}(x>0,x\ne1)`
`=(\frac{1}{\sqrt{x}(\sqrt{x}-1)}+\frac{\sqrt{x}}{(\sqrt{x}+1)(\sqrt{x}-1)}).\frac{\sqrt{x}(\sqrt{x}-1)(\sqrt{x}+1)}{(\sqrt{x}-1)(x+\sqrt{x}+1)}`
`=\frac{\sqrt{x}+1+x}{\sqrt{x}(\sqrt{x}+1)(\sqrt{x}-1)}.\frac{\sqrt{x}(\sqrt{x}-1)(\sqrt{x}+1)}{(\sqrt{x}-1)(x+\sqrt{x}+1)}`
`=\frac{1}{\sqrt{x}-1}`
`b)P=1/2`
`<=>\frac{1}{\sqrt{x}-1}=1/2`
`<=>\sqrt{x}-1=2`
`<=>\sqrt{x}=3`
`<=>x=9(tm)`
Vậy `x=9` thì `P=1/2`
