计算1/a-6/a^2-6a+a-4/2(a-6),其结果等于

问题描述:

计算1/a-6/a^2-6a+a-4/2(a-6),其结果等于
A10-a/2(a-6) Ba-10/2(a-6) Ca-4/2a Da+4/2a

原式=[2(a-6)-12+a(a-4)]/[2a(a-6)]
=(2a-12-12+a²-4a)/[2a(a-6)]
=(a²-2a-24)/[2a(a-6)]
=(a-6)(a+4)/[2a(a-6)]
=(a+4)/2a
选D