(3x/x-2-x/x+2)/x/x^2-4=(3x/x-2-x/x+2)*x^2-4/x=(3x/x-2-x/x+2)*(x-2)(x+2)/x=3(x+2)-(x-2)=3x+6-x+2=2x+8当x=0时,原式=8