`#tnvt`
`P=\frac{2-\sqrt{x}}{3\sqrt{x}}(x>0)`
`P<=1`
`=>\frac{2-\sqrt{x}}{3\sqrt{x}}<=1`
`<=>\frac{2-\sqrt{x}}{3\sqrt{x}}-1<=0`
`<=>\frac{2-\sqrt{x}-3\sqrt{x}}{3\sqrt{x}}<=0`
`<=>\frac{2-4\sqrt{x}}{3\sqrt{x}}<=0`
Mà `3\sqrt{x}>x∀x>0`
`=>2-4\sqrt{x}<=0`
`<=>4\sqrt{x}>=2`
`<=>\sqrt{x}>=1/2`
`<=>x>=1/4`
Vậy với `x>=1/4` thì `P<=1`