Đáp án + giải thích các bước giải:
a) Sửa đề: `P=((x-6)/(x+3\sqrt{x})-1/\sqrt{x}+1/(\sqrt{x}+3)):(2\sqrt{x}-6)/(x+1) (x>0;x\ne9)`
`=((x-6)/(\sqrt{x}(\sqrt{x}+3))-(\sqrt{x}+3)/(\sqrt{x}(\sqrt{x}+3))+\sqrt{x}/(\sqrt{x}(\sqrt{x}+3))):(2\sqrt{x}-6)/(x+1)`
`=(x-6-\sqrt{x}-3+\sqrt{x})/(\sqrt{x}(\sqrt{x}+3)):(2\sqrt{x}-6)/(x+1)`
`=(x-9)/(\sqrt{x}(\sqrt{x}+3)) . (x+1)/(2(\sqrt{x}-3))`
`=((\sqrt{x}-3)(\sqrt{x}+3)(x+1))/(2\sqrt{x}(\sqrt{x}+3)(\sqrt{x}-3))`
`=(x+1)/(2\sqrt{x})`
`P=1`
`->(x+1)/(2\sqrt{x})=1`
`->x+1=2\sqrt{x}`
`->x-2\sqrt{x}+1=0`
`->(\sqrt{x}-1)^2=0`
`->\sqrt{x}-1=0`
`->\sqrt{x}=1`
`->x=1(TM)`
Vậy `x=1`
