Giải thích các bước giải:
`D=(\frac{5+x}{\sqrt{x}+3}-\frac{x-5}{\sqrt{x}-3}):\frac{5-3\sqrt{x}}{x-9}`
`={(\sqrt{x}-3)(5+x)-(\sqrt{x}+3)(5-x)}/{(\sqrt{x}+3)(\sqrt{x}+3)}.{(\sqrt{x}-3)(\sqrt{x}-3)}/{5-3\sqrt{x}`
`={5\sqrt{x}+x\sqrt{x}-15-3x-(x\sqrt{x}-5\sqrt{x}+3x-15)}/{(\sqrt{x}+3)(\sqrt{x}-3)}.(\sqrt{x}+3(\sqrt{x}-3)}/{5-3\sqrt{x}}`
`=(5\sqrt{x}+x\sqrt{x}-15-3x-x\sqrt{x}+5\sqrt{x}-3x+15).1/{5-3\sqrt{x}}`
`=(10\sqrt{x}-6x).{1}/{5-3\sqrt{x}}`
`={10\sqrt{x}-6x}/{5-3\sqrt{x}}`
`=2\sqrt{x}`
Học tốt!!!
