1/x^2-6x+9 + 1/2x+6 +x/9-x^2 = 0
问题描述：
1/x^2-6x+9 + 1/2x+6 +x/9-x^2 = 0
答
1/(x-3)^2+1/2(x+3)-x/(x+3)(x-3)=0
两边乘2(x+3)(x-3)^2
2(x+3)+(x-3)^2-2x(x-3)=0
2x+6+x^2-6x+9-2x^2+6x=0
x^2-2x-15=0
(x-5)(x+3)=0
x=5,x=-3
经检验,x=-2时光年公分母为0,舍去
所以x=5