2/x+3+2/3-x+2x+18/x^2-9 =[2(X-3)-2(X+3)+2X+18]/(X+3)(X-3) =2(X+3)/(X+3)(X-3) =2/(X-3) ∴X-3=±1,±2 ∴X=4,2,5,1 符合条件x的值的和为4+2+5+1=12