1.分式2/x^2-3x与4x/x^2-9的最简公分母是（x(x+3)(x-3)）；2.-1/(x-1)(x+1),2/(x+1)(x+2),3/-(x+2)(x-1)通分后得分别为-1(x+2)/(x-1)(x+1)(x+2),2(x-1)/(x-1)(x+1)(x+2),-3(x+1)/(x-1)(x+1)(x+2).如果要计算结果,把...