4a平方-8a÷(a-2)(a+1)÷[a+1÷(a-1)-a-1÷(a+1)]

问题描述:

4a平方-8a÷(a-2)(a+1)÷[a+1÷(a-1)-a-1÷(a+1)]

=4a^2-8a/(a-2)(a-1)/[a+1/(a-1)-a-1/(a+1)]
=4a^2-8a/(a-2)(a-1)/2/(a-1)(a+1)
=4a^2-4a(a+1)/(a-2)