(x+1/x+3)²÷x²-1/x²-9·(x-2)(x+1)/x-3计算=（x+1）²/(x+3)²×(x+3)(x-3)/(x+1)(x-1)×(x-2)(x+1)/(x-3)=(x-3)(x+1)/(x+3)(x-1)×(x-2)(x+1)/(x-3)=(x-2)(x+1)²/(x+3)(x-1);很高兴为...