Đáp án:
`A=2`
Giải thích các bước giải:
`A=\sqrt{x+2\sqrt{x-1}}+\sqrt{x-2\sqrt{x-1}}`
`=\sqrt{x-1+2\sqrt{x-1}+1}+\sqrt{x-1-2\sqrt{x-1}+1}`
`=\sqrt{(\sqrt{x-1}+1)^2}+\sqrt{(\sqrt{x-1}-1)^2}`
`=|\sqrt{x-1}+1|+|\sqrt{x-1}-1|`
`=\sqrt{x-1}+1+|\sqrt{x-1}-1|`
`x<=1=>x-1<=1`
`=>\sqrt{x-1}-1<=0`
`=>|\sqrt{x-1}-1|=1-\sqrt{x-1}`
`=>A=\sqrt{x-1}+1+1-\sqrt{x-1}`
`=2`