a²-(b-c)²/(a+b)²-c²=________________.

问题描述:

a²-(b-c)²/(a+b)²-c²=________________.

a²-(b-c)²/(a+b)²-c²
=(a+b-c)(a-b+c)/(a+b+c)(a+b-c)
=(a-b+c)/(a+b+c)(