1/(5a-20)+5/(a²-9a+20)
=1/[5(a-4)]+5/[(a-4)(a-5)]
=[(a-b)+25]/[5(a-4)(a-5)]
=(a-b+25)/(5a²-45a+100)
很高兴为您解答,【the 1900】团队为您答题.
请点击下面的【选为满意回答】按钮.��һ��[(a-b)+25]/[5(a-4)(a-5)]��ʲô��˼公分母是：5(a-4)(a-5)通分的过程！