初二一道数学题,求高人.2/(9-3a),(a-1)/(a²-3-2a),a/(a²-5a+6)分式的通分.【/为分数线】

∵9-3a=-3(a-3) a²-3-2a=(a-3)(a+1) a²-5a+6=(a-2)(a-3)∴最简公分母：3(a-3)(a-2)(a+1)∴2/(9-3a)=-2(a-2)(a+1)/3(a-3)(a-2)(a+1)(a-1)/(a²-3-2a)=3(a-1)(a-2)/3(a-3)(a-2)(a+1)a/(a²-5a+6)=3a...