x+4/x²+2x+4=（x+4）/(x+2)²=x(x-1)（x+4）(x-2)³/x(x-1)(x+2)(x-2)³x-5/x²-x=(x-5)/x(x-1)=（x-5）(x+2)(x-2)³/x(x-1)(x+2)(x-2)³x-3/(x-2)(x²+2x+4)=(x-3)/(x-2)³=x...