(1/a+2-1/a-2)除以2/a-2+a方-4/a乘a方/a方+4a+4
问题描述：
(1/a+2-1/a-2)除以2/a-2+a方-4/a乘a方/a方+4a+4
答
(1/a+2-1/a-2)除以2/a-2+a方-4/a乘a方/a方+4a+4
＝1/（a+2）x(a-2)/2-1/(a-2)x(a-2)/2 + (a+2)(a-2)/a xa^2/(a+2)^2
=(a-2)/2(a+2)-1/2+a(a-2)/(a+2)
=(2a-4-a-2+a^2-2a)/(a+2)
=(a^2-a-2)/(a+2)
=(a+2)(a-1)/(a+2)
=a-1