x/(x+3)-18/(x^2)-9=1打错了是x/(x+3)-18/(x^2-9）=1

x/(x+3)-18/(x^2)-9=1打错了是x/(x+3)-18/(x^2-9）=1
x/(x+3)-18/(x^2)-9=1
打错了是x/(x+3)-18/(x^2-9）=1

x/(x+3)-18/(x^2)-9=1打错了是x/(x+3)-18/(x^2-9）=1
x/(x+3)-18/(x^2-9）=1
x(x-3)-18=(x^2-9）
x^2-3x-18=x^2-9
3x=-9
x=-3
x=-3时x^2-9=0
方程无解

有题意可知X不等于+ - 3，然后，你就可以通分做了，因为要是X=+ - 3，那么就没意义了

x/(x+3)-18/(x^2-9）=1
x/(x+3)-18/[(x+3)(x-3)]=1
通分：x(x-3)/[(x+3)(x-3)]-18/[(x+3)(x-3)]=1
[x(x-3)-18]/[(x+3)(x-3)]=1
x(x-3)-18＝(x+3)(x-3)
x^2-3x-18=x^2-9
-3x-9=0
x=-3
因为原式中x+3和x^2-9作分母，不能为0,即：x不能等于+3和-3,所以此题无解。

x/(x+3)-18/(x2-9)=1
(x2-3x-18)/(x2-9) =1
(x+3)(x-6)/[(x+3)(x-3)]=1
(x-6)/(x-3) =1 (x≠-3)
x-6=x-3 (x≠±3)
-6=-3无解