原式=2/(x+3)-2/(x-3)+(2x-18)/(x+3)(x-3)
=(2x-6-2x-6+2x+18)/(x+3)(x-3)
=(2x+6)/(x+3)(x-3)
=2/(x-3)是整数
所以x-3是2的约数
x-3=1,-1,2,-2
x=4,-2,5,1
原式=2/(x+3)-2/(x-3)+(2x-18)/(x+3)(x-3)
=(2x-6-2x-6+2x+18)/(x+3)(x-3)
=(2x+6)/(x+3)(x-3)
=2/(x-3)是整数
所以x-3是2的约数
x-3=1,-1,2,-2
x=4,-2,5,1