Question

Answer 1

`a)P=((x-2)/(x+2sqrtx)+1/(sqrtx+2))*(sqrtx+1)/(sqrtx-1)(x>0,x ne 1)`

`=((x-2+sqrtx)/(x+2sqrtx))*(sqrtx+1)/(sqrtx-1)`

`=((sqrtx+2)(sqrtx-1))/(sqrtx(sqrtx+2))*(sqrtx+1)/(sqrtx-1)`

`=(sqrtx-1)/sqrtx*(sqrtx+1)/(sqrtx-1)`

`=(sqrtx+1)/sqrtx`

`c)2P=2sqrtx+5`

`<=>(2sqrtx+2)/sqrtx=2sqrtx+5`

`<=>2sqrtx+2=2x+5sqrtx`

`<=>2x+3sqrtx-2=0`

Đặt `a=sqrtx`

`pt<=>2a^2+3a-2=0`

`Delta=9+16=25`

`<=>a_1=1/2(tm).a=-2(l)`

`<=>sqrtx=1/2`

`<=>x=1/4`

Vậy `x=1/4` thì ...