hiupppppppppppppppppppppppppp \

`{3x+1}/(x-1)^2-1/{x+1}+{x+3}/{1-x^2}`

`={(3x+1)(x+1)}/{(x-1)^2(x+1)}-{(x-1)(x+1)}/{(x+1)^2(x-1)}-{(x+3)(x+1)}/{(x-1)(x+1)(x+1)}`

`={(3x+1)(x+1)-(x-1)(x+1)-(x+3)(x+1)}/{(x+1)^2(x-1)}`

`={3x^2+3x+x+1-x^2+1-x^2-x-3x-3}/{(x+1)^2(x-1)}`

`={x^2-1}/{(x+1)(x^2-1)}`

`=1/{x+1}`