解：原式=[3x/(x-1)-x/(x+1)]×[(x²-1)/x]={3x(x+1)/[(x-1)(x+1)]-x(x-1)/[(x-1)(x+1)]}×[(x-1)(x+1)/x]=[3x(x+1)-x(x-1)]/x=(3x²+3x-x²+x)/x=(2x²+4x)/x=2x+4=2×2+4=8
