`ĐKXĐ: x>=0`
`E=(\sqrtx -2)/(\sqrtx+1)=(\sqrtx+1-3)/(\sqrtx +1) =1-3/(\sqrtx+1)<=1`
`=> E<=1(1)`
Do `x>=0=>\sqrtx +1>=1>0`
`=>3/(\sqrtx+1)>=3`
`=>-3/(\sqrtx+1) <=-3`
`<=>1-3/(\sqrtx +1) <=-2=> E<=-2(2)`
Từ `(1)(2)=>-2<=E<=1`
`=> E in {-2;-1;0;1}`
`+)`` E=-2=>(\sqrtx -2)/(\sqrtx +1)=-2`
`=>\sqrtx-2=-2\sqrtx=-2`
`<=>3\sqrtx=0`
`<=>\sqrtx=0`
`<=>x=0(tm)`
`+)`` E=-1=> (\sqrtx -2)/(\sqrtx +1)=-1`
`=>\sqrtx -3=-\sqrtx -1`
`<=>2\sqrtx = 1`
`<=>x= 1/4(tm)`
`+)``E=0=>(\sqrtx -2)/(\sqrtx +1)=0`
`=>\sqrtx-2=0`
`<=>\sqrtx=2`
`<=>x=4(tm)`
`+)``E=1=> (\sqrtx -2)/(\sqrtx +1)=1`
`=>\sqrtx-2=\sqrtx+1`
`<=>0\sqrtx=3`
`=>x= Ф(ktm)`
Vậy `x in{1/4;0;4}` thì E nguyên.
