（一）2/[(x-1)(x-3)]-1/[(x-2)(x-3)]+3/[(x+2)(x-1) ]=[2(x-2)-(x-1)]/[(x-1)(x-2)(x-3)]+3/[(x+2)(x-1)] =(2x-4-x+1))/[(x-1)(x-2)(x-3)]+3/[(x+2)(x-1)] =(x-3)/[(x-1)(x-2)(x-3)]+3/[(x+2)(x-1)] =1/[(x-1)(x-2)...