原式=(m-3)/[3m(m-2)]·[﹙m+2﹚﹙m+2﹚-5]/﹙m-2﹚=(m-3)/[3m(m-2)]·(m-2)/[﹙m+2﹚﹙m+2﹚-5]=(m-3)/3m[﹙m??-4﹚-5]=﹙m-3﹚/3m??-27m=﹙m-3﹚/3m(m??-9)=﹙m-3﹚/3m﹙m+3﹚﹙m-3﹚=1/3m2+9m因为m是方程x2+3x-1=0,则m??+3m-1=0即m2=1-3m带入原式得1/3-9m+9m=1/3