Rút gọn `A=(x^2 -4)/2 \sqrt{4/(x^2 -4x+4)}` với `x\ne 2`
2 câu trả lời
`A=(x^2 -4)/2\sqrt{4/(x^2 -4x+4)}`
Điều kiện : `x\ne 2`
`=((x-2)(x+2))/2\sqrt{4/((x-2)^2)}`
`=((x-2)(x+2))/2 . (\sqrt{4})/(\sqrt{(x-2)^2})`
`=((x-2)(x+2))/2 . 2/(|x-2|)`
* Nếu `x-2>0=>x>2`
`=>A=((x-2)(x+2))/2 . 2/(x-2)`
`=x+2`
* Nếu `x-2<0=>x<2`
`=>A=((x-2)(x+2))/2 . 2/(-(x-2))`
`=>A=-(x+2)`
`=>A=-x-2`
