Sossssss........!!!

Đáp án:

`C=((2sqrt(x)+x)/(xsqrt(x)-1)-(1)/(sqrt(x)-1)):(1-(sqrt(x))/(x+sqrt(x)+1))` với `x \ne 1; x>=0`

`=[(2sqrt(x)+x)/((sqrt(x)-1)(x+sqrt(x)+1))-(x+sqrt(x)+1)/((sqrt(x)-1)(x+sqrt(x)+1))]:(x+sqrt(x)+1-sqrt(x))/(x+sqrt(x)+1)`
`=(sqrt(x)+1)/((sqrt(x)-1)(x+sqrt(x)+1)):(x+1)/(x+sqrt(x)+1)`
`=(1)/(x+sqrt(x)+1):(x+1)/(x+sqrt(x)+1)`
`=(1)/(x+1)`

Để `C` có giá trị nguyên:

`C=(1)/(x+1) in Z`

`=> x+1 in Ư(1)={+-1}`

TH1:

`x+1=1 <=> x=0` (tm)

TH2:

`x+1=-1 <=> x=-2` (ktm)

Vậy với `x=0` thì `C` có giá trị nguyên