[a²/(a+1）-a+1]÷a²/(a²-1)
=[a²-(a-1)(a+1)]/(a+1）÷a²/(a+1)(a-1)
=(a²-a²+1)/(a+1）×(a+1)(a-1)/a²
=1/(a+1）×(a+1)(a-1)/a²
=(a-1)/a²
担心手机不显示平方符号,图片格式
[a²/(a+1）-a+1]÷a²/(a²-1)
=[a²-(a-1)(a+1)]/(a+1）÷a²/(a+1)(a-1)
=(a²-a²+1)/(a+1）×(a+1)(a-1)/a²
=1/(a+1）×(a+1)(a-1)/a²
=(a-1)/a²
担心手机不显示平方符号,图片格式