Đáp án:
`(-3\sqrt{x})/(2(\sqrt{x}+2))`
Giải thích các bước giải:
`C=(\sqrt{x}/(3+\sqrt{x})+(x+9)/(9-x)):((3\sqrt{x}+1)/(x-3\sqrt{x})-1/\sqrt{x})`
`=(\sqrt{x}(3-\sqrt{x})+x+9)/((3+\sqrt{x})(3-\sqrt{x})):(3\sqrt{x}+1-(\sqrt{x}-3))/(\sqrt{x}(\sqrt{x}-3))`
`=(3\sqrt{x}-x+x+9)/((3+\sqrt{x})(3-\sqrt{x})):(3\sqrt{x}+1-\sqrt{x}+3)/(\sqrt{x}(\sqrt{x}-3))`
`=(3(\sqrt{x}+3))/((3+\sqrt{x})(3-\sqrt{x})):(2(\sqrt{x}+2))/(\sqrt{x}(\sqrt{x}-3))`
`=3/(3-\sqrt{x}). (\sqrt{x}(\sqrt{x}-3))/(2(\sqrt{x}+2))`
`=(-3)/(\sqrt{x}-3). (\sqrt{x}(\sqrt{x}-3))/(2(\sqrt{x}+2))`
`=(-3\sqrt{x})/(2(\sqrt{x}+2))`
