a: \(P=\dfrac{x+\sqrt{x}+1-x+\sqrt{x}-1+x+1}{\sqrt{x}}\)
\(=\dfrac{x+2\sqrt{x}+1}{\sqrt{x}}\)
b: Để P=9/2 thì \(\dfrac{x+2\sqrt{x}+1}{\sqrt{x}}=\dfrac{9}{2}\)
\(\Leftrightarrow2x-5\sqrt{x}+2=0\)
=>x=1/4 hoặc x=4
`[40]`
`Đk: x ne 0, x ne 1, x >=0`.
`a, = ((sqrtx-1)(x + sqrt x + 1))/(sqrtx(sqrtx-1)) - ((sqrtx+1)(x-sqrtx+1))/(sqrtx(sqrtx+1)) + (sqrtx+1)/x`
`= (x+sqrtx+1)/(sqrtx) - (x-sqrtx+1)/(sqrtx) + (sqrtx+1)/x`
`= 2 + (sqrt x + 1)/x`
`b, P = 9/2 -> 2 + (sqrt x+1)/x = 9/2`
`(sqrtx+1)/x = 2,5`
`-> sqrt x + 1 = 2,5 x`
`-> x = 0,745 ...`