题目的原型是不是（x+3)/(x^2-3x)-(x-1)/(x^2-6x+9)
如果是的话,化简的结果应该是=(x-9)/x(x-3)^2
具体步骤如下
=（x+3）/x(x-3)-(x-1)/(x-3)^2
=1/(x-3)((x+3)/x-(x-1)/(x-3))
=1/(x-3)((x^2-9-x^2+x)/x(x-3))
=1/(x-3)((x-9)/x(x-3))
=(x-9)/x(x-3)^2