(a-a-b分之ab)除以a-b分之a的平方

问题描述:

(a-a-b分之ab)除以a-b分之a的平方

[a- ab/(a-b)]÷[a²/(a-b)]
=[a(a-b)-ab]/a²
=(a²-ab-ab)/a²
=(a²-2ab)/a²
=1 - 2b/a