Đáp án + Giải thích các bước giải:
`a//`
`P=(2x)/(x-25)+(5)/(\sqrt{x}-5)+(5)/(\sqrt{x}+5)`
`=(2x)/((\sqrt{x}+5)(\sqrt{x}-5))+(5)/(\sqrt{x}-5)+(5)/(\sqrt{x}+5)`
`=(2x+5(\sqrt{x}+5)+5(\sqrt{x}-5))/((\sqrt{x}+5)(\sqrt{x}-5))`
`=(2x+5\sqrt{x}+25+5\sqrt{x}-25)/((\sqrt{x}+5)(\sqrt{x}-5))`
`=(2x+10\sqrt{x})/((\sqrt{x}+5)(\sqrt{x}-5))`
`=(2\sqrt{x}(\sqrt{x}+5))/((\sqrt{x}+5)(\sqrt{x}-5))`
`=(2\sqrt{x})/(\sqrt{x}-5)`
`b//`
`P=-(1)/(3)`
`<=>(2\sqrt{x})/(\sqrt{x}-5)=-(1)/(3)`
`<=>3.2\sqrt{x}=-(\sqrt{x}-5)`
`<=>6\sqrt{x}=-\sqrt{x}+5`
`<=>6\sqrt{x}+\sqrt{x}=5`
`<=>7\sqrt{x}=5`
`<=>\sqrt{x}=(5)/(7)`
`<=>x=(25)/(49) (TM)`
