`#huy`
`Q=((1-x\sqrt{x})/(1-\sqrt{x})+\sqrt{x}).((1-\sqrt{x})/(1-x))^2`
`=[((1-\sqrt{x})+(1+\sqrt{x}+x))/(1-\sqrt{x})].[(1-\sqrt{x})/((1-\sqrt{x}).(1+\sqrt{x}))]^2`
`=(1+\sqrt{x}+x+\sqrt{x}).(1/(1+\sqrt{x}))^2`
`=(1+2\sqrt{x}+x). 1/(1+\sqrt{x})^2`
`=(1+\sqrt{x})^(2) . 1/((1+\sqrt{x})^2)`
`=1`
`->A`