Học sinh nguu 0 biết làm hellpppppppppppppppppppp

Đáp án:

 `c)`

`\frac{x+1}{x-3}-\frac{1-x}{x+3}-\frac{1x.(1-x)}{9-x^{2}}` `(đk: x\ne\pm3)`

`=\frac{(x+1).(x+3)}{x^{2}-9}-\frac{(1-x).(x-3)}{x^{2}-9}+\frac{x.(1-x)}{x^{2}-9}`

`=\frac{x^{2}+3x+x+3-(x-3-x^{2}+3x)+x-x^{2}}{x^{2}-9}`

`=\frac{(x^{2}-x^{2})+(3x+x+x)+3-(-x^{2}-3+4x)}{x^{2}-9}`

`=\frac{5x+3+x^{2}+3-4x}{x^{2}-9}`

`=\frac{x^{2}+x+6}{x^{2}-9}`

 `=\frac{x^{2}+x+6}{(x-3).(x+3)}`